(10 year average) kWh/m2/day
| City | Year Avg | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
| Albuquerque | 4.97 | 2.92 | 3.97 | 4.92 | 6.3 | 6.68 | 6.94 | 6.66 | 5.8 | 5.68 | 4.18 | 3.16 | 2.5 |
| Anchorage | 2.09 | 0.21 | 0.76 | 1.68 | 3.12 | 3.98 | 4.58 | 4.25 | 3.16 | 1.98 | 0.98 | 0.37 | 0.12 |
| Annapolis | 3.98 | 1.96 | 2.8 | 3.71 | 4.55 | 5.54 | 6.03 | 5.77 | 5.34 | 4.48 | 3.4 | 2.37 | 1.81 |
| Atlanta | 4.37 | 2.31 | 3.37 | 4.08 | 5.2 | 6.02 | 6.01 | 5.81 | 5.59 | 4.76 | 3.95 | 2.98 | 2.33 |
| Billings | 3.96 | 1.55 | 2.57 | 3.52 | 4.82 | 5.63 | 6.45 | 6.39 | 5.75 | 4.67 | 3.19 | 1.77 | 1.3 |
| Birmingham | 4.34 | 2.29 | 3.31 | 4.04 | 5.14 | 5.92 | 5.98 | 5.81 | 5.7 | 4.8 | 3.93 | 2.96 | 2.25 |
| Boise | 4.24 | 1.73 | 2.72 | 3.77 | 5.22 | 5.9 | 6.57 | 7.17 | 6.12 | 5.28 | 3.29 | 1.74 | 1.46 |
| Boston | 3.58 | 1.66 | 2.5 | 3.51 | 4.13 | 5.11 | 5.47 | 5.44 | 5.05 | 4.12 | 2.84 | 1.74 | 1.4 |
| Casper | 4.25 | 1.93 | 2.8 | 3.79 | 5.13 | 5.9 | 6.68 | 6.5 | 5.9 | 5.13 | 3.59 | 2.06 | 1.65 |
| Charleston | 3.73 | 1.75 | 2.64 | 3.34 | 4.26 | 5.2 | 5.67 | 5.49 | 5.19 | 4.26 | 3.19 | 2.15 | 1.62 |
| Charlotte | 4.2 | 2.22 | 3.17 | 3.95 | 4.98 | 5.8 | 6.01 | 5.76 | 5.27 | 4.58 | 3.75 | 2.76 | 2.21 |
| Chicago | 3.72 | 1.5 | 2.45 | 3.2 | 4.48 | 5.56 | 6.07 | 5.68 | 5.27 | 4.51 | 3.07 | 1.69 | 1.26 |
| Columbia | 4.15 | 2.14 | 2.91 | 3.62 | 5.03 | 5.56 | 6.22 | 6.13 | 5.64 | 4.95 | 3.57 | 2.25 | 1.82 |
| Columbus | 3.83 | 1.64 | 2.57 | 3.26 | 4.63 | 5.4 | 6.08 | 5.73 | 5.29 | 4.74 | 3.29 | 1.96 | 1.45 |
| Denver | 4.55 | 2.25 | 3.2 | 4.32 | 5.61 | 6.11 | 6.71 | 6.5 | 5.86 | 5.47 | 4.01 | 2.59 | 1.98 |
| Detroit | 3.58 | 1.43 | 2.33 | 3.19 | 4.34 | 5.44 | 5.98 | 5.64 | 4.99 | 4.25 | 2.73 | 1.52 | 1.14 |
| Dover | 3.84 | 1.85 | 2.62 | 3.6 | 4.33 | 5.44 | 5.91 | 5.64 | 5.3 | 4.38 | 3.23 | 2.21 | 1.66 |
| Dubuque | 3.77 | 1.64 | 2.58 | 3.34 | 4.57 | 5.54 | 6.06 | 5.81 | 5.26 | 4.33 | 3.03 | 1.72 | 1.35 |
| Fargo | 3.68 | 1.44 | 2.39 | 3.36 | 4.79 | 5.62 | 5.82 | 5.94 | 5.14 | 4.01 | 2.83 | 1.59 | 1.31 |
| Great Falls | 3.79 | 1.3 | 2.36 | 3.41 | 4.84 | 5.56 | 6.18 | 6.44 | 5.53 | 4.4 | 2.9 | 1.53 | 1.11 |
| Hartford | 3.59 | 1.7 | 2.43 | 3.48 | 4.07 | 5.14 | 5.58 | 5.38 | 5.04 | 4.13 | 2.91 | 1.81 | 1.42 |
| Honolulu | 5.96 | 4.38 | 5.15 | 5.99 | 6.69 | 7.05 | 7.48 | 7.37 | 7.07 | 6.51 | 5.46 | 4.41 | 4.01 |
| Houston | 4.72 | 2.47 | 3.5 | 4.4 | 5.59 | 6.03 | 6.45 | 6.36 | 6.07 | 5.46 | 4.61 | 3.3 | 2.44 |
| Indianapolis | 3.87 | 1.67 | 2.59 | 3.28 | 4.67 | 5.46 | 6.11 | 5.79 | 5.37 | 4.76 | 3.33 | 1.97 | 1.46 |
| Jackson | 3.59 | 1.47 | 2.41 | 3.22 | 4.33 | 5.46 | 5.93 | 5.57 | 4.99 | 4.3 | 2.78 | 1.55 | 1.17 |
| Kansas City | 4.11 | 2.06 | 2.89 | 3.62 | 4.92 | 5.58 | 6.17 | 6.21 | 5.59 | 4.9 | 3.49 | 2.2 | 1.75 |
| Las Vegas | 5.3 | 3.02 | 4.13 | 5.05 | 6.57 | 7.25 | 7.69 | 7.37 | 6.42 | 6.08 | 4.26 | 3.18 | 2.6 |
| Little Rock | 4.46 | 2.36 | 3.39 | 4.01 | 5.32 | 5.71 | 6.19 | 6.15 | 5.85 | 5.25 | 4.17 | 2.95 | 2.25 |
| Los Angeles | 5.4 | 3.09 | 4.25 | 5.09 | 6.58 | 7.29 | 7.62 | 7.45 | 6.72 | 6.11 | 4.42 | 3.43 | 2.72 |
| Louisville | 3.9 | 1.71 | 2.65 | 3.32 | 4.73 | 5.38 | 6.08 | 5.79 | 5.35 | 4.8 | 3.42 | 2.1 | 1.56 |
| Manchester | 3.58 | 1.66 | 2.5 | 3.51 | 4.13 | 5.11 | 5.47 | 5.44 | 5.05 | 4.12 | 2.84 | 1.74 | 1.4 |
| Miami | 5.26 | 3.72 | 4.61 | 5.42 | 6.4 | 6.61 | 6.29 | 6.26 | 6.08 | 5.47 | 4.84 | 3.96 | 3.46 |
| Milwaukee | 3.69 | 1.43 | 2.41 | 3.29 | 4.48 | 5.6 | 6.09 | 5.74 | 5.21 | 4.34 | 2.9 | 1.6 | 1.2 |
| Minneapolis | 3.68 | 1.6 | 2.61 | 3.3 | 4.55 | 5.44 | 5.86 | 5.77 | 5.12 | 4.12 | 2.9 | 1.62 | 1.34 |
| Montpelier | 3.43 | 1.58 | 2.54 | 3.5 | 4.05 | 5 | 5.24 | 5.37 | 4.92 | 3.79 | 2.46 | 1.52 | 1.28 |
| Nashville | 4.04 | 1.94 | 2.9 | 3.54 | 4.76 | 5.57 | 5.9 | 5.86 | 5.62 | 4.63 | 3.53 | 2.45 | 1.82 |
| New Orleans | 4.76 | 2.64 | 3.73 | 4.67 | 5.8 | 6.6 | 6.15 | 6.09 | 5.7 | 5.13 | 4.48 | 3.49 | 2.68 |
| New York | 3.53 | 1.67 | 2.37 | 3.41 | 3.93 | 5.11 | 5.48 | 5.26 | 5.01 | 4.05 | 2.85 | 1.82 | 1.4 |
| Omaha | 3.98 | 1.92 | 2.76 | 3.45 | 4.74 | 5.6 | 6.14 | 6.11 | 5.46 | 4.74 | 3.34 | 2 | 1.57 |
| Philadelphia | 3.84 | 1.85 | 2.62 | 3.6 | 4.33 | 5.44 | 5.91 | 5.64 | 5.3 | 4.38 | 3.23 | 2.21 | 1.66 |
| Phoenix | 5.38 | 3.25 | 4.41 | 5.17 | 6.76 | 7.42 | 7.7 | 6.99 | 6.11 | 6.02 | 4.44 | 3.52 | 2.75 |
| Pittsburgh | 3.53 | 1.59 | 2.4 | 3.26 | 4.07 | 5.05 | 5.53 | 5.27 | 4.94 | 4.05 | 2.88 | 1.86 | 1.41 |
| Portland | 3.82 | 1.38 | 2.33 | 3.49 | 4.57 | 5.46 | 6.09 | 6.64 | 5.78 | 4.8 | 2.79 | 1.41 | 1.1 |
| Portland | 3.82 | 1.38 | 2.33 | 3.49 | 4.57 | 5.46 | 6.09 | 6.64 | 5.78 | 4.8 | 2.79 | 1.41 | 1.1 |
| Providence | 3.64 | 1.7 | 2.46 | 3.53 | 4.2 | 5.17 | 5.67 | 5.48 | 5.08 | 4.21 | 2.97 | 1.8 | 1.43 |
| Salt Lake City | 4.53 | 2.23 | 3.15 | 4.09 | 5.57 | 6.26 | 6.98 | 6.86 | 5.98 | 5.39 | 3.68 | 2.29 | 1.97 |
| San Antonio | 4.83 | 2.57 | 3.7 | 4.43 | 5.54 | 5.94 | 6.62 | 6.49 | 6.28 | 5.7 | 4.67 | 3.43 | 2.62 |
| San Francisco | 4.89 | 2.35 | 3.33 | 4.42 | 5.95 | 6.84 | 7.39 | 7.55 | 6.51 | 5.75 | 3.92 | 2.65 | 2.06 |
| Seattle | 3.53 | 1.14 | 2.04 | 3.23 | 4.26 | 5.19 | 5.75 | 6.27 | 5.46 | 4.43 | 2.5 | 1.21 | 0.9 |
| Sioux Falls | 3.87 | 1.72 | 2.71 | 3.31 | 4.65 | 5.61 | 6.1 | 6.04 | 5.42 | 4.47 | 3.2 | 1.78 | 1.43 |
| St. Louis | 4.09 | 2.02 | 2.82 | 3.52 | 4.97 | 5.56 | 6.21 | 6.05 | 5.63 | 4.91 | 3.55 | 2.21 | 1.73 |
| Trenton | 3.63 | 1.71 | 2.39 | 3.43 | 4.04 | 5.26 | 5.67 | 5.39 | 5.14 | 4.18 | 3 | 1.98 | 1.48 |
| Tulsa | 4.36 | 2.33 | 3.22 | 3.9 | 5.25 | 5.58 | 6.32 | 6.4 | 5.8 | 5.08 | 3.8 | 2.62 | 2.06 |
| Washington | 3.9 | 1.95 | 2.8 | 3.66 | 4.46 | 5.42 | 5.88 | 5.63 | 5.22 | 4.38 | 3.36 | 2.34 | 1.79 |
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.