Solar resource

Peak sun hours by state, all 50 ranked

The spread runs from 6.5 hours a day in Arizona to 3.0 in Alaska, and it decides panel counts before you pick a single product: the same 900 kWh bill needs 15 panels in Arizona sun and 33 in Alaska's. Find your state, note the hours, then let the calculator turn it into your count.

#StatePeak sun hours/daySun meterPanels for 900 kWh/moPower priceA panel's year
1Arizona 6.5desert-grade sun15 14.9¢$109
2New Mexico 6.4desert-grade sun16 14.2¢$102
3Nevada 6.2desert-grade sun16 15.0¢$105
4California 5.8strong sun17 32.0¢$208
5Hawaii 5.6strong sun18 42.9¢$270
6Colorado 5.5strong sun18 14.9¢$92
7Utah 5.5strong sun18 12.2¢$76
8Texas 5.3strong sun19 14.9¢$89
9Florida 5.2strong sun19 14.1¢$83
10Kansas 5.2strong sun19 14.2¢$83
11Oklahoma 5.1solid mid-pack sun19 12.2¢$70
12Wyoming 5.0solid mid-pack sun20 12.5¢$70
13Georgia 4.9solid mid-pack sun20 14.1¢$78
14Louisiana 4.9solid mid-pack sun20 11.7¢$65
15Nebraska 4.8solid mid-pack sun21 11.5¢$62
16South Carolina 4.8solid mid-pack sun21 14.2¢$77
17Arkansas 4.7solid mid-pack sun21 12.3¢$65
18Mississippi 4.7solid mid-pack sun21 13.4¢$71
19North Carolina 4.7solid mid-pack sun21 14.1¢$75
20Alabama 4.6solid mid-pack sun21 15.2¢$79
21Idaho 4.6solid mid-pack sun21 11.5¢$60
22Missouri 4.6solid mid-pack sun21 12.9¢$67
23South Dakota 4.6solid mid-pack sun21 12.9¢$67
24Iowa 4.4solid mid-pack sun22 13.4¢$66
25Tennessee 4.4solid mid-pack sun22 12.4¢$61
26Virginia 4.4solid mid-pack sun22 14.4¢$71
27Kentucky 4.3modest sun23 12.8¢$62
28Montana 4.3modest sun23 12.7¢$61
29North Dakota 4.3modest sun23 11.5¢$56
30Delaware 4.2modest sun23 16.6¢$78
31Illinois 4.2modest sun23 15.9¢$75
32Indiana 4.2modest sun23 14.8¢$70
33Maryland 4.2modest sun23 17.9¢$84
34Minnesota 4.2modest sun23 15.4¢$73
35New Jersey 4.1modest sun24 19.3¢$89
36Rhode Island 4.1modest sun24 28.6¢$132
37Connecticut 4.0modest sun25 28.8¢$129
38Massachusetts 4.0modest sun25 29.4¢$132
39Oregon 4.0modest sun25 14.7¢$66
40Wisconsin 4.0modest sun25 17.2¢$77
41Maine 3.9modest sun25 24.3¢$106
42New Hampshire 3.9modest sun25 23.4¢$103
43New York 3.9modest sun25 24.4¢$107
44Ohio 3.9modest sun25 16.0¢$70
45Pennsylvania 3.9modest sun25 17.8¢$78
46West Virginia 3.9modest sun25 15.1¢$66
47Michigan 3.8cloudy-country sun26 19.3¢$82
48Vermont 3.8cloudy-country sun26 21.9¢$94
49Washington 3.8cloudy-country sun26 11.9¢$51
50Alaska 3.0cloudy-country sun33 24.8¢$84

Sun figures are statewide annual averages compiled from NREL solar resource data, rounded to 0.1; panel counts assume 400W panels and the 0.77 output derate documented on the methodology page. The last two columns are EIA's 2024 average residential price for the state and what one 400-watt panel's yearly output is worth at that price, before any install cost or incentive. A statewide average is a starting point, not a site survey. Big states hide a lot of weather, and each state page below measures which way the spread runs.

Reading the number

Every 0.5 hours of sun is roughly a 10% change in what each panel produces over a year. That compounds into real money at quote time: a system bid for Denver sun (5.5) delivers about 30% less energy if your roof actually lives under Cleveland sun (3.9-ish). When a quote's production estimate implies more sun than your state's figure, ask the installer what irradiance data they used. The good ones answer with a PVWatts report for your address.

Sun is half the question

The two rightmost columns are there because the sun column on its own gets the ranking wrong. Peak sun hours across the fifty states run from 3.0 to 6.5, a little over two to one. Residential electricity prices in 2024 ran from 11.51¢ to 42.86¢, closer to four to one. The larger spread wins: what a panel is worth in a year tracks the local rate more than it tracks the local sunshine, which is why several cloudy states outrank several sunny ones on the last column. Each state page works its own version of that arithmetic.

Questions people ask

What is a peak sun hour?

One peak sun hour is one hour of sunlight at full standard strength: 1,000 watts per square meter, or 1 kWh per square meter of energy. A real day delivers weaker sun over more hours; the peak-sun-hours figure compresses the whole day into equivalent full-strength hours so panel math stays simple. Six hazy hours plus a strong midday might total 4.5 peak sun hours.

Which state has the most peak sun hours?

Arizona, at about 6.5 hours a day averaged over the year, with New Mexico (6.4) and Nevada (6.2) right behind. The cloudiest are Alaska at about 3.0 and the Pacific Northwest and Great Lakes states at 3.6 to 4.0. The full ranking is in the table above.

Which state is the best place to put solar panels?

Not the sunniest one. Sort the table above by the last column, what one 400-watt panel's yearly output is worth at the state's own electricity price, and Hawaii comes first at about $270 a year. Arizona, the sunniest state in the country by a clear margin, ranks 6th at $109, behind Rhode Island, Massachusetts and Connecticut, none of which crack 4.1 peak sun hours. Sun decides how many kilowatt-hours a panel makes. The local rate decides what they are worth, and rates vary by more than sun does.

How many peak sun hours do I get at my address?

Start with your state’s figure above, then run your street address through NREL’s free PVWatts tool for the local number; it uses decades of measured weather for your grid cell. Statewide averages hide real spread. Eastern Washington gets about 1.5 more hours a day than Seattle, and West Texas beats Houston by a similar margin.

Are peak sun hours the same as daylight hours?

No. A June day in Seattle has 16 hours of daylight but about 5 peak sun hours once cloud and sun angle are counted; a December day there has 8.5 daylight hours and barely 1 peak sun hour. Daylight is when you can see; peak sun hours are when panels earn.