Insolation Levels (Nth America)

Average Insolation (10 year average) kWh/m2/day

State City Latitude Longitude Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Avg
AL Birming han 33' 34" N 86' 45" W 2.29 3.31 4.04 5.14 5.92 5.98 5.81 5.7 4.8 3.93 2.96 2.25 4.34
AK Anchorage 61' 10" N 150' 1" W 0.21 0.76 1.68 3.12 3.98 4.58 4.25 3.16 1.98 0.98 0.37 0.12 2.09
AR little rock 32' 25" N 94' 44" W 2.36 3.39 4.01 5.32 5.71 6.19 6.15 5.85 5.25 4.17 2.95 2.25 4.46
AZ Phoenix 33 ' 26" N 112' 1" W 3.25 4.41 5.17 6.76 7.42 7.7 6.99 6.11 6.02 4.44 3.52 2.75 5.38
CA Los Angeles 34' N 118' W 3.09 4.25 5.09 6.58 7.29 7.62 7.45 6.72 6.11 4.42 3.43 2.72 5.40
CA San Francisco 38' 31" N 121' 30" W 2.35 3.33 4.42 5.95 6.84 7.39 7.55 6.51 5.75 3.92 2.65 2.06 4.89
CO Denver 39' 45" N 104' 52" W 2.25 3.2 4.32 5.61 6.11 6.71 6.5 5.86 5.47 4.01 2.59 1.98 4.55
CT Hartford 41' 44" N 72' 39" W 1.7 2.43 3.48 4.07 5.14 5.58 5.38 5.04 4.13 2.91 1.81 1.42 3.59
DE Dover 39' 8" N 75' 28" W 1.85 2.62 3.6 4.33 5.44 5.91 5.64 5.3 4.38 3.23 2.21 1.66 3.84
FL Miami 25' 48" N 80' 16" W 3.72 4.61 5.42 6.4 6.61 6.29 6.26 6.08 5.47 4.84 3.96 3.46 5.26
GA Atlanta 33' 39" N 84' 26" W 2.31 3.37 4.08 5.2 6.02 6.01 5.81 5.59 4.76 3.95 2.98 2.33 4.37
HI Honolulu 21' 20" N 157' 55" W 4.38 5.15 5.99 6.69 7.05 7.48 7.37 7.07 6.51 5.46 4.41 4.01 5.96
IA Dubuque 42' 24" N 90' 42" W 1.64 2.58 3.34 4.57 5.54 6.06 5.81 5.26 4.33 3.03 1.72 1.35 3.77
ID Boise 43' 34" N 116' 13" W 1.73 2.72 3.77 5.22 5.9 6.57 7.17 6.12 5.28 3.29 1.74 1.46 4.24
IN Indianapolis 39' 44" N 86' 17" W 1.67 2.59 3.28 4.67 5.46 6.11 5.79 5.37 4.76 3.33 1.97 1.46 3.87
IL Chicago 41' 53" N 87' 38" W 1.5 2.45 3.2 4.48 5.56 6.07 5.68 5.27 4.51 3.07 1.69 1.26 3.72
KS Kansas City 39' 12" N 94' 36" W 2.06 2.89 3.62 4.92 5.58 6.17 6.21 5.59 4.9 3.49 2.2 1.75 4.11
KY Louisville 38' 11" N 85' 44" W 1.71 2.65 3.32 4.73 5.38 6.08 5.79 5.35 4.8 3.42 2.1 1.56 3.9
LA New Orleans 29' 37" N 90' 5" W 2.64 3.73 4.67 5.8 6.6 6.15 6.09 5.7 5.13 4.48 3.49 2.68 4.76
MA Boston 42' 22" N 71' 2" W 1.66 2.5 3.51 4.13 5.11 5.47 5.44 5.05 4.12 2.84 1.74 1.4 3.58
MD Annapolis 38' 35" N 76' 21" W 1.96 2.8 3.71 4.55 5.54 6.03 5.77 5.34 4.48 3.4 2.37 1.81 3.98
ME Portland 45' 36" N 122' 36" W 1.38 2.33 3.49 4.57 5.46 6.09 6.64 5.78 4.8 2.79 1.41 1.1 3.82
MI Detroit 42' 25" N 83' 1" W 1.43 2.33 3.19 4.34 5.44 5.98 5.64 4.99 4.25 2.73 1.52 1.14 3.58
MO St.Louis 38' 45" N 90' 23" W 2.02 2.82 3.52 4.97 5.56 6.21 6.05 5.63 4.91 3.55 2.21 1.73 4.09
MN Minneapolis 44' 53" N 93' 13" W 1.6 2.61 3.3 4.55 5.44 5.86 5.77 5.12 4.12 2.9 1.62 1.34 3.68
MS Jackson 42' 16" N 84' 28" W 1.47 2.41 3.22 4.33 5.46 5.93 5.57 4.99 4.3 2.78 1.55 1.17 3.59
MT Billings 45' 48" N 108' 32" W 1.55 2.57 3.52 4.82 5.63 6.45 6.39 5.75 4.67 3.19 1.77 1.3 3.96
MT Great Falls 43' 33" N 96' 42" W 1.3 2.36 3.41 4.84 5.56 6.18 6.44 5.53 4.4 2.9 1.53 1.11 3.79
NC Charlotte 35' 13" N 80' 56" W 2.22 3.17 3.95 4.98 5.8 6.01 5.76 5.27 4.58 3.75 2.76 2.21 4.2
ND Fargo 46' 54" N 96' 48" W 1.44 2.39 3.36 4.79 5.62 5.82 5.94 5.14 4.01 2.83 1.59 1.31 3.68
NE Omaha 41' 18" N 95' 54" W 1.92 2.76 3.45 4.74 5.6 6.14 6.11 5.46 4.74 3.34 2 1.57 3.98
NH Manchester 42' 56" N 71' 26" W 1.66 2.5 3.51 4.13 5.11 5.47 5.44 5.05 4.12 2.84 1.74 1.4 3.58
NJ Trenton 40' 13" N 74' 46" W 1.71 2.39 3.43 4.04 5.26 5.67 5.39 5.14 4.18 3 1.98 1.48 3.63
NM Albuquerque 35' 3" N 106' 37" W 2.92 3.97 4.92 6.3 6.68 6.94 6.66 5.8 5.68 4.18 3.16 2.5 4.97
NV Las Vegas 36' 18" N 115' 16" W 3.02 4.13 5.05 6.57 7.25 7.69 7.37 6.42 6.08 4.26 3.18 2.6 5.3
NY New York 41' N 74' W 1.67 2.37 3.41 3.93 5.11 5.48 5.26 5.01 4.05 2.85 1.82 1.4 3.53
OH Columbus 39' 16" N 85' 54" W 1.64 2.57 3.26 4.63 5.4 6.08 5.73 5.29 4.74 3.29 1.96 1.45 3.83
OK Tulsa 36' 12" N 95' 54" W 2.33 3.22 3.9 5.25 5.58 6.32 6.4 5.8 5.08 3.8 2.62 2.06 4.36
OR Portland 45' 32" N 122' 40" W 1.38 2.33 3.49 4.57 5.46 6.09 6.64 5.78 4.8 2.79 1.41 1.1 3.82
PA Philadelphia 39' 53" N 75' 15" W 1.85 2.62 3.6 4.33 5.44 5.91 5.64 5.3 4.38 3.23 2.21 1.66 3.84
PA Pittsburgh 40' 27" N 79' 57" W 1.59 2.4 3.26 4.07 5.05 5.53 5.27 4.94 4.05 2.88 1.86 1.41 3.53
RI Providence 41' 44" N 71' 26" W 1.7 2.46 3.53 4.2 5.17 5.67 5.48 5.08 4.21 2.97 1.8 1.43 3.64
SC Columbia 38' 58" N 92' 22" W 2.14 2.91 3.62 5.03 5.56 6.22 6.13 5.64 4.95 3.57 2.25 1.82 4.15
SD Sioux Falls 45' 27" N 98' 25" W 1.72 2.71 3.31 4.65 5.61 6.1 6.04 5.42 4.47 3.2 1.78 1.43 3.87
TN Nashville 36' 7" N 86' 41" W 1.94 2.9 3.54 4.76 5.57 5.9 5.86 5.62 4.63 3.53 2.45 1.82 4.04
TX San Antonio 29' 32" N 98' 28" W 2.57 3.7 4.43 5.54 5.94 6.62 6.49 6.28 5.7 4.67 3.43 2.62 4.83
TX Houston 29' 59" N 95' 22" W 2.47 3.5 4.4 5.59 6.03 6.45 6.36 6.07 5.46 4.61 3.3 2.44 4.72
UT Salt Lake City 40' 46" N 111" 52" W 2.23 3.15 4.09 5.57 6.26 6.98 6.86 5.98 5.39 3.68 2.29 1.97 4.53
VA Washington 38' 51" N 77' 2" W 1.95 2.8 3.66 4.46 5.42 5.88 5.63 5.22 4.38 3.36 2.34 1.79 3.9
VT Montpelier 44' 16" N 72' 35" W 1.58 2.54 3.5 4.05 5 5.24 5.37 4.92 3.79 2.46 1.52 1.28 3.43
WA Seattle 47' 32" N 122' 18" W 1.14 2.04 3.23 4.26 5.19 5.75 6.27 5.46 4.43 2.5 1.21 0.9 3.53
WI Milwaukee 42' 57" N 87' 54" W 1.43 2.41 3.29 4.48 5.6 6.09 5.74 5.21 4.34 2.9 1.6 1.2 3.69
WV Charleston 38' 22" N 81' 36" W 1.75 2.64 3.34 4.26 5.2 5.67 5.49 5.19 4.26 3.19 2.15 1.62 3.73
WY Casper 42' 55" N 106' 28" W 1.93 2.8 3.79 5.13 5.9 6.68 6.5 5.9 5.13 3.59 2.06 1.65 4.25

Data courtesy of: NASA - Surface meteorology and Solar Energy Data Set
Reference:
Whitlock, C. E., et al., Release 3 NASA Surface Meteorology and
Solar Energy Data Set for Renewable Energy Industry Use.
Rise & Shine 2000, the 26th Annual Conference of the Solar
Energy Society of Canada Inc. and Solar, Oct. 21-24, 2000,
Halifax, Nova Scotia, Canada.

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