Solar Insolation - Solar Electricity Handbook 2011: A Simple Practical Guide to Solar Energy - Designing and Installing Photovoltaic Solar Electric Systems - Michael Boxwell

Solar Electricity Handbook 2011: A Simple Practical Guide to Solar Energy - Designing and Installing Photovoltaic Solar Electric Systems - Michael Boxwell (2011)

Appendix B. Solar Insolation

Solar insolation shows the daily amount of energy from the sun you can expect per square metre at your location, averaged out over the period of a month. The figures are presented as an average irradiance, measured in kilowatt-hours per square metre spread over the period of a day (kWh/m²/day).

Averages have been collated over a 22-year period between 1983 and 2005, based on a three-hour sample rate.

The book only shows solar insolation figures for the United States, Canada, Australia, New Zealand, UK and Ireland. Whilst I have tried to show this information as clearly as possible, the information is in tabular form which does not display well on some smaller eBook readers. More detailed information can be accessed at www.SolarElectricityHandbook.com, with figures for every major town and city in every country in the world, thereby allowing you to access information that is specific to your area.

Understanding this information

The amount of energy you capture from the sun differs, depending on the tilt of the solar panels. If you mount your solar panels horizontally or vertically, you will capture less energy than if you face them due south (due north in the Southern Hemisphere) and tilt them towards the sun.

The tables on the following pages show the irradiance figures based on mounting your solar panels at the following angles:

· Flat (horizontal)

· Upright

· Tilted towards the equator for best year-round performance

· Tilted for best performance during the winter months

· Tilted for best performance during the summer months

· Tilted with the angle adjusted each month throughout the year

Where the figures show the panels tilted at a fixed angle, I show this angle in the left hand column as the angle adjustment from an upright (vertical) position. On the bottom row, where the optimum tilt changes each month, I show this angle underneath each month’s irradiance figures. Please note: all angles are in degrees from vertical.

For a more detailed explanation of these figures, refer to the chapter on Calculating Solar Energy.

Solar insolation values - Australia

New South Wales

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

5.91

5.25

4.48

3.56

2.73

2.49

2.68

3.49

4.6

5.41

5.88

6.24

Upright - 0°

2.34

2.56

2.93

3.36

3.43

3.77

3.78

3.83

3.54

2.83

2.40

2.31

56° angle Year-round tilt

5.38

5.11

4.84

4.42

3.87

3.90

4.04

4.68

5.33

5.50

5.43

5.57

40° angle Best winter tilt

4.74

4.66

4.62

4.45

4.07

4.20

4.32

4.82

5.22

5.11

4.82

4.85

72° angle Best summer tilt

5.78

5.32

4.82

4.16

3.46

3.37

3.54

4.28

5.16

5.63

5.80

6.04

Tilt adjusted each month

5.78 72°

5.34 64°

4.84 56°

4.47 48°

4.07 40°

4.27 32°

4.32 40°

4.82 48°

5.33 56°

5.63 64°

5.80 72°

6.24 80°

Northern Territory

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

5.83

5.18

5.07

4.81

4.35

4.24

4.47

5.07

5.98

6.59

6.5

6.27

Upright - 0°

2.43

1.81

2.28

3.09

3.73

4.24

4.23

3.75

2.99

2.02

2.32

2.79

73° angle Year-round tilt

5.85

5.04

5.13

5.15

4.94

4.99

5.20

5.62

6.23

6.48

6.48

6.36

57° angle Best winter tilt

5.58

4.68

4.94

5.21

5.23

5.43

5.61

5.83

6.13

6.04

6.12

6.13

89° angle Best summer tilt

5.84

5.18

5.08

4.84

4.40

4.29

4.52

5.12

6.00

6.59

6.51

6.28

Tilt adjusted each month

5.84 89°

5.18 81°

5.13 73°

5.22 65°

5.23 57°

5.56 50°

5.61 57°

5.83 65°

6.23 73°

6.60 81°

6.51 89°

6.37 96°

Queensland

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

6.19

5.39

4.95

3.98

3.23

3.02

3.22

4.04

5.12

5.52

6.07

6.35

Upright - 0°

2.09

2.28

2.81

3.22

3.41

3.75

3.76

3.85

3.39

2.49

2.13

2.04

62° angle Year-round tilt

5.65

5.22

5.19

4.61

4.12

4.13

4.29

4.99

5.65

5.50

5.61

5.71

46° angle Best winter tilt

4.98

4.78

4.96

4.63

4.32

4.44

4.57

5.15

5.54

5.11

4.99

4.98

78° angle Best summer tilt

6.06

5.41

5.15

4.34

3.71

3.59

3.78

4.56

5.47

5.62

5.98

6.18

Tilt adjusted each month

6.06 78°

5.42 70°

5.19 62°

4.65 54°

4.32 46°

4.50 38°

4.57 46°

5.15 54°

5.65 62°

5.62 70°

5.98 78°

6.35 86°

South Australia

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

6.81

6.18

4.91

3.75

2.71

2.29

2.53

3.21

4.32

5.34

6.29

6.67

Upright - 0°

2.54

2.94

3.32

3.72

3.54

3.48

3.63

3.52

3.37

2.87

2.54

2.42

55° angle Year-round tilt

6.15

6.05

5.42

4.80

3.94

3.60

3.86

4.29

5.01

5.45

5.80

5.93

39° angle Best winter tilt

5.36

5.49

5.19

4.86

4.15

3.87

4.12

4.41

4.89

5.05

5.12

5.13

71° angle Best summer tilt

6.65

6.31

5.37

4.49

3.51

3.13

3.39

3.95

4.86

5.58

6.21

6.45

Tilt adjusted each month

6.65 71°

6.32 63°

5.42 55°

4.87 47°

4.15 39°

3.93 32°

4.12 39°

4.41 47°

5.01 55°

5.58 63°

6.21 71°

6.68 78°

Victoria

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

6.36

5.83

4.51

3.23

2.23

1.78

1.94

2.59

3.55

4.72

5.74

6.22

Upright - 0°

2.62

3.00

3.24

3.35

3.02

2.77

2.81

2.89

2.85

2.72

2.56

2.49

52° angle Year-round tilt

5.75

5.74

5.04

4.22

3.33

2.87

3.00

3.48

4.10

4.80

5.30

5.53

36° angle Best winter tilt

5.02

5.20

4.81

4.25

3.48

3.06

3.17

3.55

3.98

4.43

4.69

4.79

68° angle Best summer tilt

6.22

6.00

5.01

3.97

3.00

2.52

2.67

3.24

4.02

4.94

5.67

6.01

Tilt adjusted each month

6.22 68°

6.02 60°

5.04 52°

4.27 44°

3.48 36°

3.09 28°

3.17 36°

3.55 44°

4.10 52°

4.94 60°

5.67 68°

6.23 76°

Western Australia

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

8.41

7.49

5.93

4.34

3.09

2.62

2.82

3.62

5.04

6.41

7.71

8.45

Upright - 0°

2.46

3.08

3.76

4.12

3.77

3.68

3.71

3.74

3.74

3.09

2.55

2.3

58° angle Year-round tilt

7.51

7.31

6.53

5.46

4.29

3.89

4.05

4.69

5.80

6.54

7.06

7.39

42° angle Best winter tilt

6.47

6.61

6.28

5.55

4.53

4.18

4.32

4.83

5.69

6.07

6.16

6.28

74° angle Best summer tilt

8.18

7.62

6.43

5.07

3.82

3.37

3.56

4.3

5.59

6.67

7.59

8.14

Tilt adjusted each month

8.18 74°

7.63 66°

6.53 58°

5.56 50°

4.53 42°

4.25 34°

4.32 42°

4.83 50°

5.80 58°

6.67 66°

7.59 74°

8.45 82°

Solar insolation values - Canada

Alberta

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.79

1.70

3.15

4.56

5.32

5.66

5.56

4.76

3.14

1.85

0.99

0.48

Upright - 0°

1.58

2.60

3.52

3.63

3.24

3.11

3.19

3.36

3.03

2.51

1.81

0.95

36° angle Year-round tilt

1.61

2.84

4.26

5.00

4.87

4.82

4.89

4.84

3.86

2.84

1.89

0.97

20° angle Best winter tilt

1.66

2.85

4.09

4.55

4.30

4.21

4.30

4.33

3.63

2.80

1.93

1.00

52° angle Best summer tilt

1.47

2.69

4.21

5.20

5.29

5.33

5.39

5.14

3.90

2.74

1.75

0.89

Tilt adjusted each month

1.66 20°

2.86 28°

4.26 36°

5.21 44°

5.29 52°

5.72 60°

5.39 52°

5.20 44°

3.86 36°

2.85 28°

1.93 20°

1.00 12°

British Columbia

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.00

1.88

2.9

4.18

5.18

5.7

6.11

5.37

4.00

2.19

1.18

0.84

Upright - 0°

1.52

2.44

2.73

2.93

2.89

2.86

3.15

3.43

3.54

2.62

1.73

1.37

42° angle Year-round tilt

1.63

2.78

3.52

4.34

4.75

4.92

5.42

5.40

4.78

3.09

1.87

1.43

26° angle Best winter tilt

1.67

2.78

3.37

3.97

4.17

4.24

4.69

4.85

4.53

3.06

1.91

1.48

58° angle Best summer tilt

1.51

2.63

3.50

4.52

5.12

5.42

5.91

5.70

4.79

2.96

1.74

1.31

Tilt adjusted each month

1.67 26°

2.80 34°

3.52 42°

4.53 50°

5.12 58°

5.75 66°

5.91 58°

5.74 50°

4.78 42°

3.10 34°

1.91 26°

1.48 18°

Manitoba

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.24

2.17

3.43

4.74

5.57

5.84

5.92

5.00

3.45

2.25

1.42

0.99

Upright - 0°

2.15

3.01

3.50

3.48

3.16

3.00

3.15

3.28

3.07

2.81

2.34

1.84

40° angle Year-round tilt

2.24

3.37

4.41

5.08

5.13

5.05

5.27

5.04

4.09

3.26

2.47

1.87

24° angle Best winter tilt

2.31

3.39

4.24

4.65

4.51

4.42

4.57

4.53

3.87

3.24

2.54

1.95

56° angle Best summer tilt

2.04

3.18

4.34

5.26

5.53

5.57

5.74

5.31

4.12

3.12

2.27

1.69

Tilt adjusted each month

2.31 24°

3.41 32°

4.41 40°

5.26 48°

5.53 56°

5.90 64°

5.74 56°

5.36 48°

4.09 40°

3.27 32°

2.54 24°

1.95 16°

New Brunswick

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.61

2.46

3.68

4.46

4.91

5.45

5.25

4.78

3.75

2.45

1.53

1.28

Upright - 0°

2.53

3.11

3.45

3.03

2.64

2.64

2.66

2.90

3.10

2.81

2.19

2.06

45° angle Year-round tilt

2.67

3.59

4.52

4.69

4.56

4.75

4.68

4.73

4.32

3.37

2.39

2.15

29° angle Best winter tilt

2.77

3.61

4.37

4.30

4.03

4.11

4.09

4.27

4.1

3.35

2.45

2.24

61° angle Best summer tilt

2.43

3.37

4.45

4.84

4.90

5.21

5.08

4.98

4.34

3.22

2.20

1.95

Tilt adjusted each month

2.77 29°

3.62 37°

4.52 45°

4.85 53°

4.90 61°

5.48 68°

5.08 61°

5.02 53°

4.32 45°

3.38 37°

2.45 29°

2.24 22°

Newfoundland and Labrador

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.23

2.07

3.27

4.16

4.75

5.16

4.90

4.36

3.25

2.09

1.26

0.99

Upright - 0°

1.91

2.68

3.12

2.87

2.64

2.62

2.59

2.73

2.72

2.43

1.83

1.63

43° angle Year-round tilt

2.03

3.06

4.03

4.30

4.34

4.48

4.35

4.29

3.73

2.89

1.99

1.7

27° angle Best winter tilt

2.09

3.07

3.88

3.94

3.83

3.88

3.80

3.87

3.53

2.86

2.03

1.77

59° angle Best summer tilt

1.87

2.89

3.99

4.47

4.68

4.93

4.74

4.53

3.77

2.77

1.85

1.55

Tilt adjusted each month

2.09 27°

3.08 35°

4.03 43°

4.48 51°

4.68 59°

5.20 66°

4.74 59°

4.58 51°

3.73 43°

2.90 35°

2.03 27°

1.77 20°

Nova Scotia

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.54

2.39

3.47

4.29

4.98

5.57

5.49

4.85

3.91

2.66

1.57

1.21

Upright - 0°

2.85

3.27

3.34

2.84

2.59

2.59

2.66

2.87

3.28

3.23

2.49

2.25

45° angle Year-round tilt

2.89

3.70

4.39

4.45

4.62

4.85

4.90

4.82

4.62

3.82

2.64

2.27

29° angle Best winter tilt

3.06

3.77

4.26

4.09

4.07

4.18

4.26

4.34

4.40

3.84

2.74

2.4

61° angle Best summer tilt

2.56

3.42

4.28

4.61

4.96

5.31

5.32

5.06

4.60

3.60

2.39

2.01

Tilt adjusted each month

3.06 29°

3.78 37°

4.39 45°

4.61 53°

4.96 61°

5.60 68°

5.32 61°

5.10 53°

4.62 45°

3.86 37°

2.74 29°

2.42 22°

Ontario

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.53

2.35

3.29

4.35

5.12

5.88

5.87

5.02

3.92

2.64

1.55

1.24

Upright - 0°

2.63

3.04

3.02

2.83

2.61

2.64

2.74

2.91

3.21

3.07

2.29

2.21

46° angle Year-round tilt

2.71

3.50

4.04

4.50

4.75

5.12

5.24

4.98

4.58

3.68

2.47

2.24

30° angle Best winter tilt

2.85

3.55

3.91

4.13

4.19

4.41

4.55

4.49

4.36

3.69

2.56

2.37

62° angle Best summer tilt

2.41

3.25

3.96

4.65

5.10

5.6

5.69

5.23

4.56

3.48

2.25

1.99

Tilt adjusted each month

2.85 30°

3.56 38°

4.04 46°

4.66 54°

5.10 62°

5.90 70°

5.69 62°

5.27 54°

4.58 46°

3.71 38°

2.56 30°

2.39 22°

Prince Edward Island

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.35

2.10

3.22

4.28

5.40

6.05

6.04

5.22

3.91

2.34

1.29

0.98

Upright - 0°

2.09

2.63

2.98

2.9

2.89

2.88

3.00

3.20

3.30

2.70

1.81

1.51

44° angle Year-round tilt

2.21

3.04

3.90

4.42

5.01

5.23

5.37

5.20

4.57

3.23

1.98

1.6

28° angle Best winter tilt

2.29

3.05

3.75

4.05

4.40

4.50

4.65

4.68

4.33

3.20

2.02

1.65

60° angle Best summer tilt

2.03

2.87

3.87

4.59

5.40

5.75

5.85

5.48

4.58

3.09

1.84

1.47

Tilt adjusted each month

2.29 28°

3.06 36°

3.90 44°

4.60 52°

5.40 60°

6.09 68°

5.85 60°

5.52 52°

4.57 44°

3.24 36°

2.02 28°

1.65 20°

Quebec

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.51

2.44

3.60

4.51

4.97

5.48

5.21

4.70

3.49

2.15

1.40

1.18

Upright - 0°

2.42

3.16

3.44

3.10

2.71

2.7

2.69

2.91

2.91

2.47

2.03

1.97

43° angle Year-round tilt

2.55

3.61

4.46

4.7

4.59

4.76

4.64

4.66

4.02

2.95

2.21

2.04

27° angle Best winter tilt

2.64

3.64

4.31

4.31

4.05

4.12

4.05

4.20

3.81

2.93

2.26

2.12

59° angle Best summer tilt

2.33

3.40

4.40

4.87

4.93

5.23

5.04

4.91

4.04

2.83

2.04

1.85

Tilt adjusted each month

2.64 27°

3.65 35°

4.46 43°

4.88 51°

4.93 59°

5.52 66°

5.04 59°

4.95 51°

4.02 43°

2.96 35°

2.26 27°

2.13 20°

Saskatchewan

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.11

1.98

3.25

4.79

5.60

5.78

6.23

5.06

3.65

2.28

1.36

0.91

Upright - 0°

1.94

2.77

3.32

3.57

3.21

3.00

3.33

3.36

3.33

2.90

2.30

1.74

40° angle Year-round tilt

2.02

3.10

4.16

5.15

5.15

4.99

5.54

5.11

4.40

3.36

2.41

1.76

24° angle Best winter tilt

2.08

3.11

4.00

4.71

4.51

4.36

4.78

4.58

4.16

3.33

2.48

1.83

56° angle Best summer tilt

1.85

2.92

4.11

5.34

5.56

5.51

6.04

5.39

4.42

3.21

2.22

1.59

Tilt adjusted each month

2.08 24°

3.12 32°

4.16 40°

5.35 48°

5.56 56°

5.85 64°

6.04 56°

5.44 48°

4.44 40°

3.37 32°

2.48 24°

1.84 16°

Solar insolation values - Ireland

Borders Region

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.57

1.25

2.34

3.96

5.34

5.41

4.92

4.10

2.87

1.53

0.71

0.4

Upright - 0°

1.06

1.85

2.44

3.13

3.31

3.04

2.89

2.90

2.77

2.05

1.23

0.81

35° angle Year-round tilt

1.10

2.03

2.98

4.25

4.89

4.61

4.31

4.10

3.50

2.32

1.29

0.82

19° angle Best winter tilt

1.12

2.02

2.83

3.87

4.33

4.03

3.79

3.66

3.29

2.28

1.31

0.84

51° angle Best summer tilt

1.01

1.94

2.98

4.44

5.32

5.09

4.75

4.36

3.55

2.25

1.21

0.75

Tilt adjusted each month

1.12 19°

2.04 27°

2.98 35°

4.46 43°

5.32 51°

5.47 58°

4.75 51°

4.43 43°

3.50 35°

2.32 27°

1.31 19°

0.84 12°

Dublin, The Midlands and Midlands-East Regions

Flat - 90°

0.62

1.19

2.09

3.34

4.32

4.36

4.21

3.52

2.53

1.44

0.82

0.5

Upright - 0°

1.03

1.59

1.97

2.45

2.61

2.46

2.44

2.37

2.25

1.78

1.33

0.92

37° angle Year-round tilt

1.08

1.78

2.48

3.42

3.90

3.76

3.70

3.42

2.93

2.05

1.41

0.94

21° angle Best winter tilt

1.10

1.77

2.34

3.10

3.47

3.3

3.26

3.06

2.74

2.01

1.43

0.97

53° angle Best summer tilt

1.01

1.71

2.50

3.59

4.25

4.14

4.05

3.64

2.98

1.99

1.32

0.87

Tilt adjusted each month

1.10 21°

1.79 29°

2.48 37°

3.62 45°

4.25 53°

4.42 60°

4.05 53°

3.71 45°

2.93 37°

2.05 29°

1.43 21°

0.97 14°

South-East, West and South West Regions

Flat - 90°

0.67

1.26

2.15

3.46

4.46

4.53

4.41

3.72

2.66

1.52

0.87

0.56

Upright - 0°

1.06

1.65

2.00

2.52

2.66

2.51

2.52

2.48

2.35

1.86

1.37

0.99

38° angle Year-round tilt

1.13

1.86

2.53

3.54

4.04

3.90

3.88

3.63

3.08

2.16

1.47

1.02

22° angle Best winter tilt

1.15

1.84

2.40

3.22

3.59

3.43

3.43

3.25

2.88

2.12

1.49

1.05

54° angle Best summer tilt

1.05

1.79

2.55

3.72

4.39

4.30

4.25

3.86

3.13

2.10

1.37

0.94

Tilt adjusted each month

1.15 22°

1.87 30°

2.53 38°

3.74 46°

4.39 54°

4.58 62°

4.25 54°

3.92 46°

3.08 38°

2.16 30°

1.49 22°

1.05 14°

Solar insolation values - New Zealand

North Island

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

6.41

5.65

4.59

3.31

2.35

1.96

2.18

2.83

3.96

4.82

5.86

6.26

Upright - 0°

2.58

2.87

3.23

3.36

3.14

3.05

3.20

3.17

3.20

2.73

2.55

2.46

53° angle Year-round tilt

5.80

5.54

5.10

4.27

3.47

3.14

3.39

3.82

4.63

4.92

5.41

5.57

37° angle Best winter tilt

5.07

5.03

4.87

4.3

3.64

3.36

3.60

3.91

4.52

4.56

4.79

4.83

69° angle Best summer tilt

6.27

5.79

5.06

4.02

3.12

2.75

2.99

3.53

4.51

5.05

5.79

6.06

Tilt adjusted each month

6.27 69°

5.81 61°

5.10 53°

4.32 45°

3.64 37°

3.41 30°

3.60 37°

3.91 45°

4.63 53°

5.05 61°

5.79 69°

6.27 76°

South Island

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

5.75

5.01

3.92

2.67

1.82

1.36

1.60

2.28

3.39

4.50

5.49

5.82

Upright - 0°

2.75

2.94

3.18

3.14

3.05

2.64

3.01

3.08

3.17

2.90

2.76

2.67

46° angle Year-round tilt

5.21

4.98

4.56

3.77

3.19

2.63

3.03

3.49

4.23

4.66

5.09

5.07

30° angle Best winter tilt

4.54

4.50

4.34

3.78

3.35

2.81

3.23

3.57

4.10

4.28

4.47

4.39

62° angle Best summer tilt

5.64

5.23

4.55

3.56

2.85

2.30

2.67

3.23

4.13

4.82

5.47

5.55

Tilt adjusted each month

5.64 62°

5.26 54°

4.56 46°

3.80 38°

3.35 30°

2.84 22°

3.23 30°

3.57 38°

4.23 46°

4.82 54°

5.47 62°

5.84 70°

Solar insolation values - United Kingdom

London

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.75

1.37

2.31

3.57

4.59

4.86

4.82

4.20

2.81

1.69

0.92

0.60

Upright - 0°

1.20

1.80

2.18

2.58

2.7

2.64

2.71

2.80

2.47

2.07

1.43

1.01

38° angle Year-round tilt

1.27

2.04

2.76

3.67

4.17

4.2

4.25

4.16

3.26

2.41

1.53

1.05

22° angle Best winter tilt

1.30

2.03

2.62

3.34

3.66

3.69

3.76

3.73

3.06

2.37

1.56

1.08

54° angle Best summer tilt

1.19

1.95

2.77

3.84

4.52

4.63

4.66

4.41

3.31

2.33

1.43

0.97

Tilt adjusted each month

1.30 22°

2.05 30°

2.76 38°

3.86 46°

4.52 54°

4.91 62°

4.66 54°

4.46 46°

3.26 38°

2.41 30°

1.56 22°

1.08 14°

South East

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.80

1.44

2.42

3.70

4.73

4.99

5.00

4.31

2.88

1.75

0.95

0.62

Upright - 0°

1.34

1.94

2.33

2.71

2.8

2.72

2.81

2.9

2.57

2.18

1.51

1.09

38° angle Year-round tilt

1.41

2.18

2.94

3.84

4.31

4.32

4.42

4.3

3.37

2.53

1.61

1.12

22° angle Best winter tilt

1.44

2.18

2.81

3.5

3.79

3.80

3.92

3.86

3.17

2.49

1.64

1.16

54° angle Best summer tilt

1.30

2.08

2.94

4.01

4.68

4.76

4.85

4.55

3.41

2.43

1.50

1.03

Tilt adjusted each month

1.44 22°

2.20 30°

2.94 38°

4.03 46°

4.68 54°

5.05 62°

4.85 54°

4.60 46°

3.37 38°

2.53 30°

1.64 22°

1.16 14°

South West

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.81

1.51

2.49

3.91

5.13

5.37

5.28

4.37

3.07

1.74

1.01

0.65

Upright - 0°

1.26

1.98

2.36

2.83

2.97

2.84

2.9

2.88

2.72

2.09

1.54

1.08

39° angle Year-round tilt

1.34

2.25

3.00

4.07

4.7

4.64

4.68

4.34

3.60

2.45

1.65

1.13

23° angle Best winter tilt

1.37

2.24

2.86

3.72

4.13

4.08

4.07

3.90

3.40

2.41

1.68

1.16

55° angle Best summer tilt

1.25

2.14

3.00

4.24

5.08

5.12

5.12

4.59

3.64

2.36

1.54

1.04

Tilt adjusted each month

1.37 23°

2.26 31°

3.00 39°

4.26 47°

5.08 55°

5.43 62°

5.12 55°

4.65 47°

3.60 39°

2.45 31°

1.68 23°

1.16 16°

East of England

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.72

1.34

2.37

3.60

4.68

4.90

4.86

4.20

2.82

1.64

0.91

0.57

Upright - 0°

1.18

1.80

2.30

2.63

2.78

2.68

2.75

2.83

2.52

2.04

1.45

1.01

38° angle Year-round tilt

1.25

2.03

2.89

3.71

4.24

4.21

4.27

4.16

3.30

2.36

1.55

1.04

22° angle Best winter tilt

1.27

2.02

2.74

3.38

3.77

3.69

3.77

3.73

3.10

2.32

1.57

1.07

54° angle Best summer tilt

1.16

1.94

2.90

3.89

4.61

4.65

4.69

4.41

3.35

2.29

1.45

0.96

Tilt adjusted each month

1.27 22°

2.04 30°

2.89 38°

3.91 46°

4.61 54°

4.96 62°

4.69 54°

4.48 46°

3.30 38°

2.37 30°

1.57 22°

1.07 14°

East Midlands

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.64

1.31

2.20

3.37

4.44

4.51

4.50

3.82

2.59

1.54

0.8

0.51

Upright - 0°

1.07

1.80

2.11

2.47

2.67

2.53

2.59

2.59

2.31

1.93

1.27

0.94

37° angle Year-round tilt

1.13

2.01

2.64

3.45

4.01

3.88

3.95

3.74

3.01

2.22

1.36

0.96

21° angle Best winter tilt

1.15

2.00

2.51

3.13

3.56

3.40

3.48

3.35

2.81

2.18

1.37

0.99

53° angle Best summer tilt

1.05

1.92

2.66

3.62

4.37

4.28

4.33

3.98

3.06

2.15

1.27

0.89

Tilt adjusted each month

1.15 21°

2.02 29°

2.64 37°

3.65 45°

4.37 53°

4.57 60°

4.33 53°

4.05 45°

3.01 37°

2.22 29°

1.37 21°

0.99 14°

West Midlands

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.71

1.35

2.28

3.47

4.51

4.69

4.69

4.04

2.70

1.65

0.90

0.57

Upright - 0°

1.18

1.84

2.18

2.54

2.70

2.59

2.68

2.73

2.41

2.08

1.45

1.03

38° angle Year-round tilt

1.24

2.06

2.74

3.56

4.09

4.05

4.14

3.99

3.14

2.4

1.55

1.06

22° angle Best winter tilt

1.26

2.05

2.60

3.25

3.64

3.55

3.65

3.58

2.95

2.36

1.57

1.09

54° angle Best summer tilt

1.15

1.97

2.75

3.73

4.45

4.46

4.53

4.23

3.19

2.31

1.44

0.97

Tilt adjusted each month

1.26 22°

2.07 30°

2.74 38°

3.76 46°

4.45 54°

4.74 62°

4.53 54°

4.30 46°

3.14 38°

2.40 30°

1.57 22°

1.09 14°

North-East England

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.61

1.35

2.45

3.88

5.35

5.47

5.13

4.29

2.91

1.66

0.77

0.44

Upright - 0°

1.17

2.03

2.61

3.04

3.31

3.06

3.01

3.05

2.81

2.27

1.38

0.94

35° angle Year-round tilt

1.21

2.23

3.17

4.14

4.9

4.65

4.49

4.32

3.56

2.56

1.44

0.95

19° angle Best winter tilt

1.24

2.22

3.03

3.76

4.33

4.07

3.95

3.85

3.34

2.52

1.46

0.98

51° angle Best summer tilt

1.11

2.12

3.17

4.33

5.33

5.15

4.96

4.59

3.60

2.46

1.34

0.86

Tilt adjusted each month

1.24 19°

2.24 27°

3.17 35°

4.36 43°

5.33 51°

5.53 58°

4.96 51°

4.66 43°

3.56 35°

2.56 27°

1.46 19°

0.98 12°

North-West England

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.66

1.32

2.30

3.63

4.92

5.00

4.88

3.98

2.73

1.53

0.79

0.50

Upright - 0°

1.16

1.85

2.28

2.74

2.99

2.79

2.82

2.74

2.51

1.95

1.29

0.95

36° angle Year-round tilt

1.21

2.06

2.83

3.79

4.49

4.31

4.31

3.94

3.23

2.23

1.37

0.96

20° angle Best winter tilt

1.24

2.05

2.69

3.46

4.00

3.78

3.8

3.54

3.04

2.19

1.39

0.99

52° angle Best summer tilt

1.12

1.96

2.83

3.97

4.89

4.77

4.73

4.18

3.28

2.16

1.28

0.88

Tilt adjusted each month

1.24 20°

2.07 28°

2.83 36°

3.99 44°

4.89 52°

5.08 60°

4.73 52°

4.25 44°

3.23 36°

2.23 28°

1.39 20°

1.00 12°

Yorkshire and the Humber

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.62

1.30

2.30

3.51

4.69

4.78

4.64

3.89

2.67

1.54

0.75

0.47

Upright - 0°

1.12

1.86

2.31

2.64

2.86

2.68

2.7

2.68

2.46

1.99

1.25

0.92

36° angle Year-round tilt

1.16

2.06

2.85

3.64

4.24

4.09

4.07

3.83

3.16

2.28

1.32

0.94

20° angle Best winter tilt

1.19

2.04

2.71

3.31

3.77

3.58

3.58

3.42

2.96

2.24

1.34

0.97

52° angle Best summer tilt

1.08

1.96

2.86

3.82

4.63

4.50

4.47

4.08

3.21

2.2

1.24

0.86

Tilt adjusted each month

1.19 20°

2.06 28°

2.85 36°

3.85 44°

4.63 52°

4.83 60°

4.47 52°

4.15 44°

3.16 36°

2.28 28°

1.34 20°

0.97 12°

Central and Southern Scotland

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.51

1.16

2.03

3.22

4.55

4.66

4.31

3.63

2.42

1.33

0.64

0.38

Upright - 0°

0.99

1.75

2.05

2.46

2.85

2.68

2.58

2.55

2.28

1.76

1.14

0.86

34° angle Year-round tilt

1.02

1.91

2.51

3.32

4.11

3.97

3.77

3.52

2.87

1.99

1.20

0.86

18° angle Best winter tilt

1.04

1.90

2.37

3.00

3.64

3.47

3.31

3.17

2.68

1.95

1.21

0.89

50° angle Best summer tilt

0.94

1.83

2.53

3.49

4.49

4.37

4.15

3.77

2.93

1.93

1.12

0.78

Tilt adjusted each month

1.04 18°

1.92 26°

2.51 34°

3.53 42°

4.49 50°

4.72 58°

4.15 50°

3.86 42°

2.87 34°

1.99 26°

1.21 18°

0.89 10°

North Scotland

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.47

1.11

2.05

3.30

4.52

4.63

4.31

3.61

2.45

1.31

0.59

0.32

Upright - 0°

0.99

1.74

2.16

2.59

2.88

2.7

2.61

2.57

2.38

1.80

1.12

0.77

33° angle Year-round tilt

1.00

1.88

2.62

3.44

4.08

3.93

3.75

3.50

2.96

2.01

1.16

0.76

17° angle Best winter tilt

1.03

1.87

2.46

3.12

3.62

3.43

3.30

3.15

2.77

1.97

1.18

0.79

49° angle Best summer tilt

0.92

1.80

2.61

3.62

4.46

4.32

4.11

3.75

3.02

1.95

1.08

0.69

Tilt adjusted each month

1.03 17°

1.89 25°

2.62 33°

3.66 41°

4.46 49°

4.69 56°

4.11 49°

3.84 41°

2.96 33°

2.01 25°

1.18 17°

0.79 10°

South Wales

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.72

1.33

2.21

3.52

4.57

4.75

4.71

3.97

2.71

1.55

0.89

0.59

Upright - 0°

1.14

1.74

2.04

2.54

2.7

2.59

2.66

2.64

2.37

1.87

1.35

0.99

38° angle Year-round tilt

1.21

1.97

2.59

3.61

4.15

4.11

4.16

3.91

3.12

2.18

1.45

1.03

22° angle Best winter tilt

1.23

1.96

2.46

3.29

3.65

3.61

3.68

3.51

2.93

2.14

1.47

1.06

54° angle Best summer tilt

1.13

1.89

2.61

3.78

4.51

4.52

4.56

4.14

3.17

2.11

1.36

0.95

Tilt adjusted each month

1.23 22°

1.98 30°

2.59 38°

3.80 46°

4.51 54°

4.80 62°

4.56 54°

4.20 46°

3.12 38°

2.18 30°

1.47 22°

1.06 14°

North Wales

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.66

1.32

2.30

3.63

4.92

5.00

4.88

3.98

2.73

1.53

0.79

0.50

Upright - 0°

1.14

1.83

2.26

2.72

2.97

2.77

2.81

2.72

2.49

1.93

1.27

0.92

37° angle Year-round tilt

1.19

2.04

2.81

3.78

4.48

4.30

4.29

3.93

3.22

2.22

1.35

0.95

21° angle Best winter tilt

1.22

2.03

2.68

3.44

3.98

3.77

3.79

3.52

3.02

2.18

1.37

0.98

53° angle Best summer tilt

1.11

1.95

2.82

3.96

4.88

4.76

4.72

4.18

3.27

2.15

1.26

0.87

Tilt adjusted each month

1.22 21°

2.05 29°

2.81 37°

3.98 45°

4.88 53°

5.08 60°

4.72 53°

4.24 45°

3.22 37°

2.22 29°

1.37 21°

0.98 14°

Northern Ireland

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.61

1.25

2.15

3.39

4.54

4.54

4.30

3.64

2.56

1.42

0.74

0.43

Upright - 0°

1.09

1.79

2.12

2.55

2.79

2.58

2.54

2.51

2.36

1.82

1.25

0.82

35° angle Year-round tilt

1.13

1.98

2.62

3.51

4.12

3.9

3.79

3.56

3.02

2.08

1.32

0.83

19° angle Best winter tilt

1.16

1.97

2.49

3.19

3.66

3.42

3.34

3.19

2.83

2.04

1.34

0.86

51° angle Best summer tilt

1.05

1.89

2.64

3.68

4.49

4.27

4.15

3.79

3.07

2.02

1.24

0.77

Tilt adjusted each month

1.16 19°

1.99 27°

2.62 35°

3.71 43°

4.49 51°

4.59 58°

4.15 51°

3.86 43°

3.02 35°

2.08 27°

1.34 19°

0.86 12°

Solar insolation values - United States of America

Alabama

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.32

2.9

4.06

5.01

5.54

5.64

5.7

5.14

4.58

3.84

2.68

2.17

Upright - 0°

2.94

2.85

3.06

2.67

2.30

2.15

2.22

2.46

3.03

3.72

3.29

3.00

58° angle Year-round tilt

3.29

3.64

4.60

5.04

5.10

5.02

5.14

4.96

4.98

4.86

3.76

3.22

42° angle Best winter tilt

3.45

3.68

4.46

4.65

4.52

4.36

4.49

4.50

4.75

4.90

3.92

3.42

74° angle Best summer tilt

2.96

3.42

4.5

5.18

5.46

5.45

5.55

5.20

4.96

4.56

3.39

2.85

Tilt adjusted each month

3.45 42°

3.69 50°

4.60 58°

5.18 66°

5.46 74°

5.64 82°

5.55 74°

5.22 66°

4.98

58°

4.92 50°

3.92 42°

3.45 34°

Alaska

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

0.40

1.07

2.22

3.73

4.95

5.26

4.86

3.86

2.46

1.37

0.58

0.00

Upright - 0°

0.88

1.75

2.51

3.09

3.22

3.08

2.98

2.83

2.47

2.00

1.20

0.00

32° angle Year-round tilt

0.89

1.89

2.97

4.06

4.50

4.47

4.24

3.81

3.03

2.21

1.23

0.00

16° angle Best winter tilt

0.92

1.88

2.83

3.68

3.99

3.90

3.73

3.43

2.84

2.17

1.25

0.00

48° angle Best summer tilt

0.82

1.80

2.97

4.25

4.93

4.93

4.66

4.07

3.09

2.13

1.14

0.00

Tilt adjusted each month

0.92 16°

1.90 24°

2.97 32°

4.27 40°

4.93 48°

5.35 56°

4.66 48°

4.16 40°

3.03 32°

2.21 24°

1.25 16°

0.00

8°

Arizona

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

3.20

4.07

5.45

6.62

7.37

7.52

6.78

5.97

5.45

4.48

3.50

2.95

Upright - 0°

4.63

4.59

4.29

3.33

2.57

2.28

2.34

2.70

3.60

4.51

4.76

4.63

57° angle Year-round tilt

4.92

5.55

6.45

6.83

6.74

6.57

6.08

5.78

6.03

5.82

5.24

4.74

41° angle Best winter tilt

5.28

5.74

6.34

6.33

5.87

5.58

5.26

5.22

5.78

5.93

5.57

5.14

73° angle Best summer tilt

4.28

5.04

6.20

6.96

7.26

7.23

6.60

6.05

5.95

5.39

4.60

4.06

Tilt adjusted each month

5.28 41°

5.74 49°

6.45 57°

6.97 65°

7.26 73°

7.52 80°

6.60 73°

6.07 65°

6.03 57°

5.94 49°

5.57 41°

5.24 34°

Arkansas

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.39

3.03

4.01

5.19

5.51

5.91

6.02

5.52

4.74

3.71

2.60

2.15

Upright - 0°

3.14

3.09

3.07

2.80

2.33

2.22

2.31

2.64

3.20

3.62

3.23

3.02

55° angle Year-round tilt

3.45

3.88

4.56

5.24

5.10

5.26

5.44

5.36

5.20

4.70

3.66

3.21

39° angle Best winter tilt

3.64

3.94

4.44

4.84

4.52

4.57

4.76

4.86

4.98

4.74

3.82

3.42

71° angle Best summer tilt

3.08

3.62

4.46

5.38

5.44

5.72

5.88

5.61

5.16

4.41

3.30

2.83

Tilt adjusted each month

3.64 39°

3.94 47°

4.56 55°

5.38 63°

5.44 71°

5.91 78°

5.88 71°

5.63 63°

5.20 55°

4.75 47°

3.82 39°

3.45 32°

California

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.18

3.09

4.65

6.08

7.21

7.93

7.79

7.02

5.64

4.12

2.63

1.99

Upright - 0°

3.35

3.68

4.09

3.53

2.96

2.69

2.82

3.46

4.34

4.83

3.96

3.37

51° angle Year-round tilt

3.52

4.36

5.72

6.32

6.64

6.91

6.95

6.95

6.64

5.86

4.23

3.41

35° angle Best winter tilt

3.73

4.46

5.61

5.83

5.79

5.84

5.95

6.25

6.39

5.98

4.47

3.66

67° angle Best summer tilt

3.12

4.02

5.52

6.49

7.16

7.63

7.60

7.29

6.52

5.40

3.75

2.97

Tilt adjusted each month

3.73 35°

4.46 43°

5.72 51°

6.49 59°

7.16 67°

7.95 74°

7.60 67°

7.31 59°

6.64 51°

5.98 43°

4.47 35°

3.71 28°

Colorado

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.41

3.27

4.49

5.42

6.28

6.70

6.35

5.68

5.03

3.90

2.67

2.18

Upright - 0°

4.20

4.18

4.05

3.25

2.80

2.60

2.64

2.99

3.90

4.66

4.30

4.21

50° angle Year-round tilt

4.27

4.85

5.58

5.62

5.81

5.90

5.72

5.60

5.87

5.60

4.52

4.12

34° angle Best winter tilt

4.58

4.99

5.47

5.17

5.10

5.05

4.96

5.05

5.63

5.71

4.79

4.47

66° angle Best summer tilt

3.72

4.43

5.39

5.78

6.24

6.47

6.21

5.87

5.79

5.17

3.98

3.53

Tilt adjusted each month

4.58 34°

4.99 42°

5.58 50°

5.78 58°

6.24 66°

6.73 74°

6.21 66°

5.89 58°

5.87 50°

5.71 42°

4.79 34°

4.56 26°

Connecticut

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.88

2.73

3.76

4.52

5.23

5.80

5.54

5.00

4.11

3.01

1.97

1.63

Upright - 0°

3.20

3.50

3.41

2.83

2.57

2.52

2.54

2.79

3.23

3.45

3.00

3.01

48° angle Year-round tilt

3.29

4.05

4.62

4.65

4.85

5.07

5.01

4.92

4.73

4.17

3.21

3.00

32° angle Best winter tilt

3.49

4.14

4.50

4.28

4.28

4.38

4.37

4.45

4.51

4.20

3.35

3.21

64° angle Best summer tilt

2.91

3.73

4.50

4.80

5.20

5.53

5.42

5.16

4.71

3.92

2.88

2.61

Tilt adjusted each month

3.49 32°

4.14 40°

4.62 48°

4.80 56°

5.20 64°

5.81 72°

5.42 64°

5.19 56°

4.73 48°

4.21 40°

3.35 32°

3.25 24°

Delaware

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.97

2.73

3.69

4.65

5.27

5.67

5.50

5.05

4.25

3.33

2.24

1.77

Upright - 0°

2.99

3.16

3.10

2.77

2.46

2.36

2.40

2.68

3.15

3.65

3.21

2.93

51° angle Year-round tilt

3.17

3.78

4.35

4.73

4.86

5.01

4.95

4.92

4.78

4.51

3.50

3.00

35° angle Best winter tilt

3.34

3.84

4.22

4.36

4.29

4.34

4.32

4.44

4.56

4.54

3.66

3.20

67° angle Best summer tilt

2.82

3.52

4.26

4.89

5.21

5.47

5.36

5.17

4.77

4.23

3.14

2.64

Tilt adjusted each month

3.34 35°

3.85 43°

4.35 51°

4.89 59°

5.21 67°

5.68 74°

5.36 67°

5.20 59°

4.78 51°

4.56 43°

3.66 35°

3.23 28°

Florida

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

3.56

4.44

5.29

6.11

6.49

5.97

5.55

5.26

4.76

4.52

3.78

3.35

Upright - 0°

4.03

4.07

3.44

2.62

2.06

1.88

1.91

2.15

2.68

3.68

4.04

4.07

63° angle Year-round tilt

4.66

5.39

5.80

6.11

5.98

5.38

5.08

5.06

4.96

5.27

4.85

4.51

47° angle Best winter tilt

4.96

5.56

5.69

5.68

5.28

4.69

4.50

4.62

4.75

5.33

5.11

4.85

79° angle Best summer tilt

4.11

4.94

5.61

6.23

6.39

5.82

5.45

5.26

4.93

4.93

4.32

3.92

Tilt adjusted each month

4.96 47°

5.56 55°

5.80 63°

6.23 71°

6.39 79°

5.97 86°

5.45 79°

5.28 71°

4.96 63°

5.34 55°

5.11 47°

4.92 40°

Georgia

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.50

3.12

4.28

5.19

5.80

5.59

5.72

5.17

4.46

3.91

2.82

2.36

Upright - 0°

3.21

3.14

3.23

2.74

2.34

2.13

2.21

2.46

2.92

3.76

3.48

3.32

56° angle Year-round tilt

3.55

3.96

4.86

5.24

5.36

5.00

5.18

5.01

4.82

4.92

3.96

3.52

40° angle Best winter tilt

3.74

4.02

4.74

4.86

4.74

4.37

4.55

4.55

4.60

4.97

4.15

3.76

72° angle Best summer tilt

3.17

3.69

4.74

5.38

5.72

5.42

5.58

5.23

4.80

4.60

3.55

3.09

Tilt adjusted each month

3.74 40°

4.03 48°

4.86 56°

5.38 64°

5.72 72°

5.59 80°

5.58 72°

5.25 64°

4.82 56°

4.98 48°

4.15 40°

3.80 32°

Hawaii

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

4.09

5.06

5.85

6.58

6.97

7.35

7.21

6.88

6.36

5.41

4.34

3.90

Upright - 0°

4.06

4.12

3.33

2.33

1.77

2.80

1.69

2.01

3.00

3.96

4.22

4.12

69° angle Year-round tilt

4.98

5.84

6.24

6.50

6.43

7.37

6.52

6.63

6.60

6.10

5.24

4.83

53° angle Best winter tilt

5.29

6.03

6.13

6.04

5.65

6.92

5.65

6.03

6.34

6.20

5.56

5.19

85° angle Best summer tilt

4.40

5.34

6.03

6.62

6.89

7.43

7.08

6.88

6.50

5.67

4.65

4.21

Tilt adjusted each month

5.29 53°

6.03 61°

6.24 69°

6.63 77°

6.89 85°

7.46 92°

7.08 85°

6.89 77°

6.60 69°

6.21 61°

5.56 53°

5.27 46°

Idaho

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.72

2.66

4.07

5.38

6.36

7.24

7.37

6.44

4.99

3.43

1.97

1.49

Upright - 0°

3.17

3.67

4.01

3.53

3.08

2.98

3.18

3.66

4.33

4.56

3.35

3.00

47° angle Year-round tilt

3.21

4.15

5.28

5.72

5.92

6.26

6.56

6.51

6.14

5.28

3.49

2.96

31° angle Best winter tilt

3.41

4.25

5.16

5.26

5.17

5.31

5.61

5.85

5.89

5.38

3.67

3.17

63° angle Best summer tilt

2.83

3.82

5.10

5.88

6.38

6.89

7.16

6.83

6.04

4.88

3.11

2.57

Tilt adjusted each month

3.41 31°

4.25 39°

5.28 47°

5.88 55°

6.38 63°

7.26 70°

7.16 63°

6.85 55°

6.14 47°

5.38 39°

3.67 31°

3.21 24°

Illinois

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.92

2.55

3.62

4.69

5.40

5.90

6.12

5.38

4.57

3.32

2.10

1.71

Upright - 0°

2.91

2.91

3.06

2.83

2.54

2.44

2.59

2.86

3.48

3.70

2.95

2.84

50° angle Year-round tilt

3.08

3.48

4.28

4.80

5.01

5.23

5.52

5.29

5.24

4.53

3.22

2.90

34° angle Best winter tilt

3.24

3.53

4.15

4.42

4.42

4.52

4.80

4.78

5.01

4.58

3.36

3.09

66° angle Best summer tilt

2.74

3.25

4.19

4.95

5.36

5.71

5.99

5.54

5.19

4.24

2.90

2.55

Tilt adjusted each month

3.24 34°

3.54 42°

4.28 50°

4.95 58°

5.36 66°

5.92 74°

5.99 66°

5.57 58°

5.24 50°

4.59 42°

3.36 34°

3.12 26°

Indiana

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.83

2.54

3.55

4.49

5.19

5.91

5.98

5.24

4.55

3.26

2.02

1.57

Upright - 0°

2.70

2.89

2.99

2.70

2.46

2.44

2.56

2.80

3.46

3.60

2.78

2.47

50° angle Year-round tilt

2.87

3.46

4.18

4.57

4.80

5.24

5.40

5.15

5.21

4.42

3.05

2.56

34° angle Best winter tilt

3.02

3.51

4.05

4.21

4.25

4.53

4.70

4.65

4.98

4.46

3.17

2.72

66° angle Best summer tilt

2.57

3.24

4.10

4.71

5.14

5.72

5.85

5.39

5.17

4.15

2.76

2.27

Tilt adjusted each month

3.02 34°

3.52 42°

4.18 50°

4.72 58°

5.14 66°

5.93 74°

5.85 66°

5.42 58°

5.21 50°

4.48 42°

3.17 34°

2.74 26°

Iowa

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.91

2.56

3.62

4.56

5.39

6.12

6.02

5.32

4.41

3.14

2.02

1.64

Upright - 0°

3.26

3.15

3.23

2.84

2.62

2.59

2.67

2.94

3.50

3.67

3.10

3.04

48° angle Year-round tilt

3.35

3.68

4.40

4.68

4.99

5.33

5.43

5.26

5.13

4.42

3.31

3.04

32° angle Best winter tilt

3.55

3.74

4.27

4.31

4.40

4.59

4.71

4.74

4.90

4.46

3.46

3.25

64° angle Best summer tilt

2.96

3.42

4.30

4.84

5.36

5.83

5.90

5.52

5.09

4.14

2.97

2.65

Tilt adjusted each month

3.55 32°

3.75 40°

4.40 48°

4.84 56°

5.36 64°

6.13 72°

5.90 64°

5.55 56°

5.13 48°

4.47 40°

3.46 32°

3.29 24°

Kansas

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.15

2.72

3.91

4.80

5.61

6.15

6.37

5.48

4.67

3.41

2.30

1.92

Upright - 0°

3.40

3.13

3.32

2.84

2.56

2.46

2.60

2.86

3.50

3.76

3.32

3.32

51° angle Year-round tilt

3.57

3.75

4.66

4.89

5.16

5.41

5.70

5.36

5.33

4.64

3.61

3.36

35° angle Best winter tilt

3.78

3.81

4.53

4.50

4.54

4.65

4.93

4.83

5.09

4.68

3.78

3.60

67° angle Best summer tilt

3.16

3.50

4.55

5.05

5.54

5.93

6.21

5.63

5.29

4.35

3.24

2.93

Tilt adjusted each month

3.78 35°

3.81 43°

4.66 51°

5.06 59°

5.54 67°

6.17 74°

6.21 67°

5.66 59°

5.33 51°

4.69 43°

3.78 35°

3.64 28°

Louisiana

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.59

3.25

4.31

5.21

5.79

5.65

5.66

5.30

4.72

4.03

3.04

2.56

Upright - 0°

2.95

3.02

3.01

2.57

2.19

2.00

2.07

2.34

2.89

3.55

3.42

3.22

60° angle Year-round tilt

3.41

3.95

4.76

5.23

5.35

5.07

5.14

5.11

5.02

4.85

4.03

3.54

44° angle Best winter tilt

3.57

4.00

4.63

4.86

4.75

4.43

4.53

4.65

4.80

4.89

4.21

3.77

76° angle Best summer tilt

3.08

3.69

4.65

5.35

5.71

5.48

5.53

5.33

4.99

4.55

3.63

3.13

Tilt adjusted each month

3.57 44°

4.01 52°

4.76 60°

5.35 68°

5.71 76°

5.65 84°

5.53 76°

5.35 68°

5.02 60°

4.90 52°

4.21 44°

3.80 36°

Maine

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.69

2.57

3.64

4.43

4.87

5.35

5.28

4.85

3.78

2.56

1.60

1.33

Upright - 0°

3.25

3.61

3.52

2.91

2.52

2.50

2.56

2.84

3.10

3.01

2.51

2.57

46° angle Year-round tilt

3.28

4.07

4.63

4.59

4.50

4.64

4.69

4.80

4.39

3.60

2.68

2.58

30° angle Best winter tilt

3.48

4.16

4.50

4.21

3.96

4.01

4.09

4.32

4.17

3.60

2.78

2.74

62° angle Best summer tilt

2.88

3.75

4.52

4.76

4.84

5.09

5.10

5.05

4.39

3.41

2.43

2.27

Tilt adjusted each month

3.48 30°

4.16 38°

4.63 46°

4.76 54°

4.84 62°

5.37 70°

5.10 62°

5.09 54°

4.39 46°

3.62 38°

2.78 30°

2.76 22°

Maryland

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.94

2.68

3.67

4.63

5.31

5.58

5.53

4.94

4.19

3.33

2.19

1.71

Upright - 0°

2.89

3.06

3.06

2.75

2.47

2.33

2.40

2.62

3.09

3.63

3.08

2.75

51° angle Year-round tilt

3.09

3.68

4.31

4.70

4.89

4.93

4.97

4.80

4.70

4.50

3.37

2.84

35° angle Best winter tilt

3.24

3.73

4.18

4.33

4.31

4.27

4.34

4.34

4.47

4.53

3.52

3.02

67° angle Best summer tilt

2.76

3.44

4.23

4.86

5.24

5.38

5.39

5.04

4.69

4.22

3.04

2.51

Tilt adjusted each month

3.24 35°

3.74 43°

4.31 51°

4.87 59°

5.24 67°

5.59 74°

5.39 67°

5.08 59°

4.70 51°

4.55 43°

3.52 35°

3.04 28°

Massachusetts

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.80

2.62

3.61

4.46

5.13

5.50

5.60

4.99

4.04

2.93

1.89

1.54

Upright - 0°

3.15

3.40

3.30

2.83

2.56

2.47

2.59

2.81

3.22

3.41

2.94

2.91

48° angle Year-round tilt

3.22

3.91

4.44

4.59

4.75

4.79

5.05

4.91

4.67

4.10

3.13

2.90

32° angle Best winter tilt

3.42

3.99

4.32

4.22

4.19

4.15

4.40

4.43

4.45

4.12

3.27

3.10

64° angle Best summer tilt

2.85

3.62

4.34

4.74

5.10

5.24

5.49

5.16

4.66

3.86

2.82

2.53

Tilt adjusted each month

3.42 32°

3.99 40°

4.44 48°

4.75 56°

5.10 64°

5.51 72°

5.49 64°

5.19 56°

4.67 48°

4.14 40°

3.27 32°

3.14 24°

Michigan

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.78

2.51

3.44

4.45

5.24

6.07

5.93

5.03

4.13

2.79

1.69

1.41

Upright - 0°

3.13

3.22

3.11

2.84

2.61

2.64

2.70

2.86

3.33

3.20

2.47

2.55

47° angle Year-round tilt

3.20

3.71

4.20

4.59

4.86

5.29

5.36

4.97

4.81

3.86

2.67

2.56

31° angle Best winter tilt

3.39

3.78

4.07

4.22

4.29

4.55

4.65

4.49

4.59

3.87

2.77

2.73

63° angle Best summer tilt

2.83

3.44

4.11

4.74

5.21

5.78

5.82

5.22

4.78

3.64

2.43

2.25

Tilt adjusted each month

3.39 31°

3.78 39°

4.20 47°

4.74 55°

5.21 63°

6.09 70°

5.82 63°

5.25 55°

4.81 47°

3.89 39°

2.77 31°

2.75 24°

Minnesota

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.71

2.55

3.44

4.54

5.32

5.96

6.05

5.19

4.00

2.78

1.76

1.37

Upright - 0°

3.41

3.65

3.33

3.03

2.75

2.73

2.87

3.08

3.39

3.49

3.03

2.81

45° angle Year-round tilt

3.39

4.08

4.36

4.76

4.96

5.19

5.40

5.20

4.76

4.08

3.15

2.77

29° angle Best winter tilt

3.62

4.18

4.24

4.37

4.36

4.47

4.68

4.68

4.54

4.12

3.30

2.97

61° angle Best summer tilt

2.97

3.74

4.25

4.91

5.33

5.68

5.87

5.46

4.73

3.83

2.82

2.42

Tilt adjusted each month

3.62 29°

4.18 37°

4.36 45°

4.92 53°

5.33 61°

5.99 68°

5.87 61°

5.48 53°

4.76 45°

4.13 37°

3.30 29°

3.00

22°

Mississippi

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.52

3.24

4.24

5.34

5.89

5.98

5.80

5.36

4.75

3.99

2.94

2.39

Upright - 0°

3.08

3.20

3.09

2.72

2.30

2.12

2.17

2.46

3.04

3.71

3.53

3.17

58° angle Year-round tilt

3.48

4.07

4.75

5.39

5.43

5.33

5.25

5.17

5.12

4.94

4.05

3.44

42° angle Best winter tilt

3.66

4.14

4.62

5.00

4.80

4.62

4.60

4.70

4.90

4.99

4.24

3.65

74° angle Best summer tilt

3.12

3.79

4.64

5.52

5.80

5.79

5.66

5.41

5.09

4.63

3.64

3.03

Tilt adjusted each month

3.66 42°

4.14 50°

4.75 58°

5.52 66°

5.80 74°

5.98 82°

5.66 74°

5.43 66°

5.12 58°

5.00 50°

4.24 42°

3.69 34°

Missouri

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.09

2.71

3.85

4.94

5.53

5.95

6.18

5.52

4.62

3.42

2.23

1.89

Upright - 0°

3.13

3.04

3.21

2.90

2.52

2.40

2.54

2.85

3.42

3.70

3.07

3.10

51° angle Year-round tilt

3.32

3.67

4.54

5.05

5.11

5.27

5.57

5.41

5.24

4.59

3.37

3.17

35° angle Best winter tilt

3.51

3.72

4.41

4.65

4.51

4.55

4.84

4.89

5.01

4.63

3.52

3.38

67° angle Best summer tilt

2.95

3.42

4.43

5.20

5.47

5.74

6.04

5.67

5.20

4.30

3.04

2.77

Tilt adjusted each month

3.51 35°

3.73 43°

4.54 51°

5.20 59°

5.47 67°

5.96 74°

6.04 67°

5.70 59°

5.24 51°

4.65 43°

3.52 35°

3.42 28°

Montana

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.64

2.51

3.65

4.72

5.60

6.31

6.58

5.70

4.30

2.83

1.83

1.37

Upright - 0°

2.59

3.19

3.41

3.22

2.95

2.94

3.18

3.45

3.62

3.31

2.73

2.25

43° angle Year-round tilt

2.73

3.67

4.48

4.98

5.21

5.48

5.87

5.71

5.04

3.95

2.94

2.34

27° angle Best winter tilt

2.83

3.69

4.33

4.58

4.59

4.71

5.08

5.14

4.79

3.94

3.03

2.44

59° angle Best summer tilt

2.48

3.45

4.41

5.14

5.61

6.00

6.39

6.00

5.04

3.76

2.70

2.12

Tilt adjusted each month

2.83 27°

3.71 35°

4.48 43°

5.15 51°

5.61 59°

6.34 66°

6.39 59°

6.04 51°

5.04 43°

3.97 35°

3.03 27°

2.45 20°

Nebraska

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.09

2.68

3.83

4.78

5.57

6.35

6.35

5.48

4.63

3.35

2.26

1.86

Upright - 0°

3.55

3.26

3.39

2.93

2.64

2.60

2.71

2.97

3.63

3.90

3.51

3.50

49° angle Year-round tilt

3.65

3.82

4.65

4.91

5.16

5.54

5.73

5.41

5.38

4.70

3.72

3.47

33° angle Best winter tilt

3.88

3.90

4.53

4.53

4.55

4.77

4.96

4.89

5.15

4.76

3.92

3.74

65° angle Best summer tilt

3.20

3.55

4.53

5.07

5.54

6.06

6.22

5.67

5.33

4.39

3.32

3.00

Tilt adjusted each month

3.88 33°

3.90 41°

4.65 49°

5.07 57°

5.54 65°

6.36 72°

6.22 65°

5.70 57°

5.38 49°

4.77 41°

3.92 33°

3.79 26°

Nevada

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.29

3.15

4.61

5.85

7.01

7.77

7.76

6.89

5.60

4.06

2.60

2.11

Upright - 0°

3.84

3.94

4.16

3.48

2.98

2.74

2.90

3.49

4.42

4.91

4.10

3.95

51° angle Year-round tilt

3.95

4.60

5.75

6.10

6.47

6.77

6.93

6.85

6.67

5.89

4.33

3.91

35° angle Best winter tilt

4.21

4.72

5.64

5.61

5.64

5.72

5.93

6.15

6.41

6.01

4.58

4.22

67° angle Best summer tilt

3.46

4.22

5.55

6.26

6.97

7.47

7.58

7.17

6.55

5.42

3.83

3.36

Tilt adjusted each month

4.21 35°

4.72 43°

5.75 51°

6.26 59°

6.97 67°

7.79 74°

7.58 67°

7.20 59°

6.67 51°

6.01 43°

4.58 35°

4.30 28°

New Hampshire

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.74

2.62

3.61

4.43

4.92

5.42

5.47

4.91

3.92

2.72

1.71

1.46

Upright - 0°

3.17

3.54

3.38

2.85

2.51

2.48

2.58

2.82

3.16

3.17

2.63

2.86

47° angle Year-round tilt

3.23

4.03

4.51

4.57

4.55

4.71

4.90

4.85

4.54

3.80

2.81

2.84

31° angle Best winter tilt

3.42

4.12

4.38

4.20

4.01

4.08

4.26

4.36

4.31

3.81

2.92

3.03

63° angle Best summer tilt

2.85

3.72

4.40

4.73

4.89

5.16

5.32

5.10

4.53

3.59

2.54

2.47

Tilt adjusted each month

3.42 31°

4.12 39°

4.51 47°

4.74 55°

4.89 63°

5.43 70°

5.32 63°

5.13 55°

4.54 47°

3.83 39°

2.92 31°

3.07 24°

New Jersey

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.92

2.71

3.69

4.57

5.21

5.61

5.51

4.97

4.15

3.13

2.07

1.66

Upright - 0°

3.03

3.25

3.18

2.77

2.49

2.39

2.45

2.69

3.15

3.47

2.99

2.83

50° angle Year-round tilt

3.18

3.84

4.41

4.66

4.81

4.96

4.97

4.85

4.70

4.26

3.24

2.88

34° angle Best winter tilt

3.35

3.91

4.28

4.28

4.25

4.29

4.33

4.38

4.48

4.28

3.38

3.07

66° angle Best summer tilt

2.82

3.57

4.32

4.81

5.16

5.42

5.38

5.10

4.69

4.01

2.93

2.53

Tilt adjusted each month

3.35 34°

3.91 42°

4.41 50°

4.82 58°

5.16 66°

5.63 74°

5.38 66°

5.13 58°

4.70 50°

4.30 42°

3.38 34°

3.10 26°

New Mexico

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

3.04

3.85

5.14

6.32

7.04

7.22

6.51

5.81

5.41

4.39

3.29

2.81

Upright - 0°

4.80

4.49

4.27

3.39

2.70

2.42

2.44

2.79

3.80

4.73

4.83

4.87

54° angle Year-round tilt

4.98

5.39

6.20

6.48

6.47

6.33

5.85

5.66

6.11

5.93

5.18

4.85

38° angle Best winter tilt

5.36

5.56

6.10

5.98

5.66

5.40

5.08

5.12

5.87

6.05

5.52

5.28

70° angle Best summer tilt

4.31

4.91

5.96

6.65

6.96

6.95

6.34

5.92

6.02

5.47

4.54

4.13

Tilt adjusted each month

5.36 38°

5.56 46°

6.20 54°

6.65 62°

6.96 70°

7.22 78°

6.34 70°

5.95 62°

6.11 54°

6.05 46°

5.52 38°

5.40 30°

New York

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.74

2.60

3.57

4.34

5.04

5.64

5.55

4.97

3.95

2.80

1.76

1.47

Upright - 0°

3.02

3.39

3.27

2.76

2.54

2.52

2.58

2.82

3.15

3.22

2.63

2.73

47° angle Year-round tilt

3.09

3.89

4.40

4.46

4.67

4.92

5.02

4.91

4.56

3.88

2.83

2.73

31° angle Best winter tilt

3.28

3.97

4.27

4.10

4.13

4.26

4.37

4.43

4.35

3.89

2.94

2.91

63° angle Best summer tilt

2.74

3.60

4.29

4.61

5.01

5.37

5.44

5.16

4.55

3.66

2.56

2.39

Tilt adjusted each month

3.28 31°

3.97 39°

4.40 47°

4.62 55°

5.01 63°

5.65 70°

5.44 63°

5.19 55°

4.56 47°

3.91 39°

2.94 31°

2.94 24°

North Carolina

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.43

3.05

4.20

5.22

5.73

5.80

5.68

5.08

4.43

3.76

2.73

2.30

Upright - 0°

3.39

3.24

3.33

2.87

2.43

2.25

2.30

2.52

3.05

3.82

3.64

3.56

54° angle Year-round tilt

3.66

4.00

4.87

5.29

5.29

5.16

5.15

4.93

4.86

4.87

4.03

3.67

38° angle Best winter tilt

3.87

4.07

4.75

4.89

4.69

4.49

4.51

4.47

4.64

4.93

4.24

3.94

70° angle Best summer tilt

3.24

3.72

4.74

5.44

5.66

5.61

5.55

5.15

4.84

4.55

3.60

3.20

Tilt adjusted each month

3.87 38°

4.07 46°

4.87 54°

5.44 62°

5.66 70°

5.80 78°

5.55 70°

5.18 62°

4.86 54°

4.94 46°

4.24 38°

4 30°

North Dakota

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.48

2.35

3.47

4.77

5.72

6.26

6.49

5.48

4.06

2.73

1.71

1.27

Upright - 0°

2.36

3.02

3.29

3.29

3.06

2.98

3.22

3.39

3.47

3.25

2.61

2.15

43° angle Year-round tilt

2.49

3.46

4.28

5.01

5.27

5.43

5.79

5.50

4.78

3.85

2.80

2.22

27° angle Best winter tilt

2.58

3.48

4.13

4.60

4.63

4.67

5.01

4.95

4.54

3.83

2.88

2.32

59° angle Best summer tilt

2.28

3.26

4.22

5.19

5.68

5.96

6.30

5.78

4.78

3.67

2.57

2.01

Tilt adjusted each month

2.58 27°

3.50 35°

4.28 43°

5.19 51°

5.68 59°

6.30 66°

6.30 59°

5.82 51°

4.78 43°

3.87 35°

2.88 27°

2.32 20°

Ohio

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.77

2.49

3.31

4.47

5.18

5.64

5.76

5.11

4.26

3.08

1.86

1.46

Upright - 0°

2.64

2.86

2.76

2.70

2.47

2.39

2.51

2.74

3.23

3.37

2.51

2.28

50° angle Year-round tilt

2.81

3.43

3.86

4.54

4.77

4.98

5.18

4.99

4.84

4.16

2.78

2.38

34° angle Best winter tilt

2.95

3.47

3.73

4.17

4.21

4.31

4.50

4.50

4.61

4.18

2.88

2.51

66° angle Best summer tilt

2.53

3.21

3.80

4.69

5.12

5.44

5.62

5.24

4.82

3.92

2.54

2.12

Tilt adjusted each month

2.95 34°

3.47 42°

3.86 50°

4.70 58°

5.12 66°

5.66 74°

5.62 66°

5.28 58°

4.84 50°

4.20 42°

2.88 34°

2.52 26°

Oklahoma

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.59

3.20

4.29

5.40

5.84

6.32

6.73

5.86

4.81

3.72

2.75

2.33

Upright - 0°

3.70

3.43

3.39

2.94

2.44

2.31

2.46

2.79

3.31

3.73

3.64

3.59

54° angle Year-round tilt

3.97

4.23

4.98

5.47

5.38

5.59

6.03

5.70

5.32

4.79

4.05

3.71

38° angle Best winter tilt

4.21

4.31

4.86

5.05

4.75

4.82

5.22

5.15

5.09

4.83

4.25

3.98

70° angle Best summer tilt

3.50

3.92

4.85

5.63

5.76

6.10

6.55

5.97

5.28

4.49

3.62

3.23

Tilt adjusted each month

4.21 38°

4.31 46°

4.98 54°

5.63 62°

5.76 70°

6.33 78°

6.55 70°

5.99 62°

5.32 54°

4.85 46°

4.25 38°

4.04 30°

Oregon

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.41

2.24

3.26

4.33

5.26

6.19

6.85

6.04

4.55

2.82

1.49

1.16

Upright - 0°

2.40

2.91

3.03

2.83

2.68

2.74

3.06

3.48

3.91

3.47

2.23

2.04

46° angle Year-round tilt

2.49

3.35

4.02

4.47

4.86

5.35

6.07

6.07

5.53

4.10

2.41

2.09

30° angle Best winter tilt

2.61

3.39

3.89

4.10

4.27

4.58

5.20

5.44

5.28

4.12

2.49

2.20

62° angle Best summer tilt

2.23

3.12

3.95

4.64

5.23

5.88

6.63

6.39

5.47

3.85

2.20

1.86

Tilt adjusted each month

2.61 30°

3.40 38°

4.02 46°

4.64 54°

5.23 62°

6.22 70°

6.63 62°

6.42 54°

5.53 46°

4.14 38°

2.49 30°

2.21 22°

Pennsylvania

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.87

2.65

3.52

4.32

5.11

5.44

5.50

4.86

4.03

3.07

1.97

1.58

Upright - 0°

2.91

3.16

3.00

2.63

2.46

2.35

2.45

2.64

3.05

3.39

2.78

2.62

50° angle Year-round tilt

3.07

3.74

4.17

4.38

4.71

4.82

4.96

4.74

4.55

4.16

3.03

2.69

34° angle Best winter tilt

3.23

3.80

4.04

4.03

4.17

4.18

4.33

4.28

4.33

4.18

3.16

2.86

66° angle Best summer tilt

2.73

3.48

4.09

4.53

5.05

5.26

5.37

4.98

4.54

3.92

2.75

2.38

Tilt adjusted each month

3.23 34°

3.80 42°

4.17 50°

4.54 58°

5.05 66°

5.46 74°

5.37 66°

5.01 58°

4.55 50°

4.20 42°

3.16 34°

2.88 26°

Rhode Island

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.89

2.69

3.75

4.54

5.31

5.76

5.57

5.07

4.13

3.07

1.98

1.62

Upright - 0°

3.25

3.44

3.40

2.85

2.60

2.52

2.55

2.83

3.26

3.58

3.04

2.99

48° angle Year-round tilt

3.33

3.97

4.61

4.67

4.93

5.04

5.04

5.01

4.76

4.31

3.24

2.98

32° angle Best winter tilt

3.53

4.06

4.49

4.30

4.35

4.36

4.40

4.52

4.55

4.34

3.39

3.19

64° angle Best summer tilt

2.93

3.67

4.49

4.82

5.28

5.49

5.45

5.25

4.74

4.03

2.91

2.60

Tilt adjusted each month

3.53 32°

4.06 40°

4.61 48°

4.82 56°

5.28 64°

5.77 72°

5.45 64°

5.28 56°

4.76 48°

4.36 40°

3.39 32°

3.23 24°

South Carolina

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.52

3.14

4.28

5.41

5.88

5.90

5.75

5.13

4.44

3.80

2.83

2.39

Upright - 0°

3.33

3.19

3.26

2.85

2.37

2.18

2.23

2.46

2.93

3.67

3.59

3.49

56° angle Year-round tilt

3.67

4.03

4.89

5.47

5.40

5.23

5.18

4.95

4.81

4.80

4.05

3.67

40° angle Best winter tilt

3.87

4.09

4.76

5.05

4.77

4.53

4.53

4.49

4.58

4.83

4.25

3.93

72° angle Best summer tilt

3.27

3.76

4.77

5.62

5.79

5.70

5.60

5.19

4.79

4.50

3.64

3.22

Tilt adjusted each month

3.87 40°

4.09 48°

4.89 56°

5.62 64°

5.79 72°

5.90 80°

5.60 72°

5.21 64°

4.81 56°

4.85 48°

4.25 40°

3.97 32°

South Dakota

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.75

2.54

3.61

4.79

5.83

6.51

6.60

5.75

4.42

3.04

1.93

1.47

Upright - 0°

3.44

3.52

3.48

3.16

2.91

2.84

2.99

3.33

3.77

3.91

3.40

3.04

46° angle Year-round tilt

3.45

3.98

4.58

5.02

5.41

5.62

5.85

5.76

5.33

4.57

3.53

3.01

30° angle Best winter tilt

3.68

4.07

4.45

4.60

4.73

4.80

5.03

5.17

5.08

4.62

3.71

3.21

62° angle Best summer tilt

3.03

3.67

4.47

5.19

5.83

6.19

6.39

6.06

5.28

4.27

3.14

2.62

Tilt adjusted each month

3.68 30°

4.07 38°

4.58 46°

5.19 54°

5.83 62°

6.54 70°

6.39 62°

6.09 54°

5.33 46°

4.63 38°

3.71 30°

3.25 22°

Tennessee

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.06

2.72

3.83

4.97

5.47

5.79

5.79

5.30

4.63

3.62

2.43

1.88

Upright - 0°

2.72

2.81

3.00

2.77

2.38

2.26

2.33

2.63

3.23

3.69

3.13

2.69

54° angle Year-round tilt

3.00

3.51

4.38

5.02

5.04

5.13

5.22

5.14

5.13

4.70

3.52

2.87

38° angle Best winter tilt

3.14

3.54

4.25

4.63

4.46

4.45

4.55

4.65

4.90

4.74

3.67

3.03

70° angle Best summer tilt

2.71

3.29

4.30

5.17

5.40

5.58

5.64

5.39

5.10

4.41

3.18

2.55

Tilt adjusted each month

3.14 38°

3.55 46°

4.38 54°

5.18 62°

5.40 70°

5.79 78°

5.64 70°

5.42 62°

5.13 54°

4.76 46°

3.67 38°

3.05 30°

Texas

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.83

3.41

4.40

5.25

5.62

6.36

6.56

5.94

4.97

4.05

3.07

2.63

Upright - 0°

3.35

3.21

3.07

2.57

2.16

2.05

2.14

2.50

3.03

3.55

3.45

3.35

60° angle Year-round tilt

3.82

4.18

4.86

5.27

5.19

5.65

5.90

5.72

5.31

4.87

4.07

3.67

44° angle Best winter tilt

4.03

4.25

4.74

4.89

4.61

4.88

5.12

5.18

5.08

4.90

4.25

3.91

76° angle Best summer tilt

3.41

3.89

4.75

5.39

5.54

6.15

6.38

5.98

5.27

4.57

3.66

3.24

Tilt adjusted each month

4.03 44°

4.25 52°

4.86 60°

5.39 68°

5.54 76°

6.36 84°

6.38 76°

6.00 68°

5.31 60°

4.92 52°

4.25 44°

3.95 36°

Utah

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.31

3.11

4.47

5.54

6.55

7.31

7.08

6.11

5.10

3.76

2.45

2.07

Upright - 0°

4.10

3.99

4.10

3.36

2.91

2.73

2.83

3.21

4.03

4.53

3.92

4.07

50° angle Year-round tilt

4.17

4.62

5.61

5.76

6.04

6.38

6.33

6.04

6.01

5.43

4.14

3.99

34° angle Best winter tilt

4.46

4.74

5.49

5.30

5.27

5.41

5.43

5.43

5.76

5.52

4.37

4.32

66° angle Best summer tilt

3.64

4.24

5.42

5.93

6.51

7.03

6.91

6.34

5.93

5.03

3.67

3.43

Tilt adjusted each month

4.46 34°

4.74 42°

5.61 50°

5.93 58°

6.51 66°

7.34 74°

6.91 66°

6.37 58°

6.01 50°

5.53 42°

4.37 34°

4.39 26°

Vermont

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.61

2.53

3.54

4.34

4.86

5.43

5.49

4.81

3.72

2.45

1.50

1.26

Upright - 0°

3.06

3.55

3.42

2.87

2.53

2.54

2.65

2.84

3.06

2.85

2.30

2.38

46° angle Year-round tilt

3.08

4.00

4.49

4.51

4.50

4.72

4.89

4.77

4.33

3.41

2.46

2.40

30° angle Best winter tilt

3.27

4.09

4.37

4.14

3.97

4.08

4.26

4.30

4.11

3.41

2.55

2.54

62° angle Best summer tilt

2.72

3.68

4.38

4.66

4.84

5.17

5.31

5.02

4.32

3.24

2.24

2.11

Tilt adjusted each month

3.27 30°

4.09 38°

4.49 46°

4.67 54°

4.84 62°

5.45 70°

5.31 62°

5.05 54°

4.33 46°

3.43 38°

2.55 30°

2.56 22°

Virginia

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.17

2.83

3.89

4.76

5.38

5.63

5.56

4.98

4.28

3.58

2.43

1.94

Upright - 0°

3.11

3.10

3.15

2.73

2.42

2.28

2.34

2.56

3.04

3.79

3.32

3.00

53° angle Year-round tilt

3.34

3.79

4.53

4.82

4.97

5.00

5.02

4.83

4.74

4.75

3.65

3.12

37° angle Best winter tilt

3.52

3.84

4.40

4.44

4.39

4.34

4.39

4.38

4.52

4.79

3.82

3.32

69° angle Best summer tilt

2.98

3.53

4.43

4.97

5.31

5.44

5.42

5.07

4.72

4.44

3.28

2.74

Tilt adjusted each month

3.52 37°

3.85 45°

4.53 53°

4.97 61°

5.31 69°

5.64 76°

5.42 69°

5.09 61°

4.74 53°

4.81 45°

3.82 37°

3.35 30°

Washington

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.06

1.93

2.94

4.05

4.99

5.51

5.88

5.20

3.98

2.25

1.25

0.91

Upright - 0°

1.55

2.42

2.69

2.76

2.73

2.72

2.97

3.23

3.42

2.62

1.79

1.43

43° angle Year-round tilt

1.68

2.79

3.52

4.15

4.55

4.76

5.21

5.18

4.68

3.13

1.95

1.51

27° angle Best winter tilt

1.72

2.79

3.37

3.80

4.01

4.10

4.51

4.65

4.43

3.10

1.99

1.56

59° angle Best summer tilt

1.56

2.65

3.50

4.33

4.91

5.24

5.68

5.47

4.70

3.00

1.82

1.39

Tilt adjusted each month

1.72 27°

2.81 35°

3.532 43°

4.34 51°

4.91 59°

5.55 66°

5.68 59°

5.51 51°

4.68 43°

3.14 35°

1.99 27°

1.56 20°

West Virginia

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.85

2.49

3.51

4.58

5.09

5.82

5.63

4.99

4.31

3.33

2.12

1.65

Upright - 0°

2.56

2.66

2.84

2.68

2.37

2.36

2.39

2.61

3.14

3.53

2.81

2.46

52° angle Year-round tilt

2.79

3.27

4.05

4.64

4.70

5.15

5.07

4.85

4.82

4.42

3.13

2.59

36° angle Best winter tilt

2.91

3.29

3.92

4.27

4.16

4.45

4.43

4.39

4.59

4.44

3.25

2.74

68° angle Best summer tilt

2.51

3.07

3.98

4.79

5.03

5.62

5.49

5.09

4.80

4.15

2.84

2.31

Tilt adjusted each month

2.91 36°

3.30 44°

4.05 52°

4.79 60°

5.03 68°

5.83 76°

5.49 68°

5.12 60°

4.82 52°

4.46 44°

3.25 36°

2.75 28°

Wisconsin

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

1.80

2.67

3.58

4.49

5.33

5.97

5.87

5.05

4.01

2.76

1.79

1.52

Upright - 0°

3.34

3.63

3.34

2.89

2.67

2.63

2.71

2.89

3.25

3.23

2.82

3.05

47° angle Year-round tilt

3.39

4.13

4.45

4.64

4.92

5.18

5.24

4.99

4.67

3.87

3.00

3.01

31° angle Best winter tilt

3.60

4.22

4.32

4.25

4.33

4.45

4.54

4.49

4.44

3.88

3.12

3.22

63° angle Best summer tilt

2.98

3.81

4.35

4.80

5.30

5.67

5.71

5.25

4.66

3.65

2.70

2.61

Tilt adjusted each month

3.60 31°

4.22 39°

4.45 47°

4.80 55°

5.30 63°

5.99 70°

5.71 63°

5.29 55°

4.67 47°

3.90 39°

3.12 31°

3.26 24°

Wyoming

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Flat - 90°

2.13

2.92

4.10

5.13

6.14

6.92

6.65

5.82

4.79

3.52

2.34

1.89

Upright - 0°

3.81

3.78

3.76

3.18

2.84

2.73

2.80

3.15

3.83

4.28

3.83

3.76

49° angle Year-round tilt

3.88

4.37

5.12

5.32

5.66

5.98

5.96

5.76

5.65

5.11

4.03

3.69

33° angle Best winter tilt

4.13

4.47

4.99

4.89

4.96

5.09

5.13

5.18

5.40

5.18

4.25

3.99

65° angle Best summer tilt

3.39

4.02

4.97

5.49

6.10

6.58

6.50

6.05

5.59

4.75

3.58

3.18

Tilt adjusted each month

4.13 33°

4.47 41°

5.12 49°

5.49 57°

6.10 65°

6.93 72°

6.50 65°

6.08 57°

5.65 49°

5.19 41°

4.25 33°

4.05 26°