U.S. Solar Insolation & ASHRAE Climatic Design Database

Standardized meteorological benchmarks from the National Renewable Energy Laboratory (NREL NSRDB & PVWatts V8),ASHRAE Handbook — Fundamentals (Chapters 14 & 18), and the U.S. Energy Information Administration (EIA).

50-State Solar & Climatic Benchmark Table

54 Meteorological Stations Listed
State & MetroZone☀️ Peak Sun Hours📐 Opt. Tilt❄️ ASHRAE 99% Winter🔥 ASHRAE 1% Summer⚡ EIA Rate
Alabama (Birmingham)3A4.82 kWh/m²/d30°22.1°F93.6°F$0.154/kWh
Alaska (Anchorage)73.15 kWh/m²/d55°-6.7°F72.3°F$0.248/kWh
Arizona (Phoenix)2B6.55 kWh/m²/d30°40.8°F109.8°F$0.141/kWh
Arkansas (Little Rock)3A4.75 kWh/m²/d31°21.6°F95.7°F$0.128/kWh
California (Los Angeles)3B5.62 kWh/m²/d31°44.2°F86.2°F$0.315/kWh
California (Central) (Fresno / Central Valley)3B5.78 kWh/m²/d33°32°F101.5°F$0.315/kWh
California (North) (San Francisco / Bay Area)3C5.38 kWh/m²/d34°38.5°F78.4°F$0.315/kWh
Colorado (Denver)5B5.48 kWh/m²/d36°1.2°F92.3°F$0.151/kWh
Connecticut (Hartford)5A4.31 kWh/m²/d37°4.8°F89.2°F$0.289/kWh
Delaware (Wilmington)4A4.58 kWh/m²/d35°14.5°F90.7°F$0.165/kWh
District of Columbia (Washington D.C.)4A4.62 kWh/m²/d35°16.9°F92.8°F$0.168/kWh
Florida (Central) (Orlando)2A5.37 kWh/m²/d26°39.2°F93.9°F$0.156/kWh
Florida (South) (Miami)1A5.49 kWh/m²/d23°48.7°F91.6°F$0.156/kWh
Georgia (Atlanta)3A4.88 kWh/m²/d30°21.7°F92.5°F$0.143/kWh
Hawaii (Honolulu)1A5.86 kWh/m²/d19°62.1°F89.2°F$0.442/kWh
Idaho (Boise)5B4.95 kWh/m²/d39°11.5°F96.3°F$0.112/kWh
Illinois (Chicago)5A4.22 kWh/m²/d38°-1.3°F90.1°F$0.169/kWh
Indiana (Indianapolis)5A4.38 kWh/m²/d36°3.4°F89.5°F$0.152/kWh
Iowa (Des Moines)5A4.51 kWh/m²/d37°-6°F90.5°F$0.138/kWh
Kansas (Wichita)4A5.12 kWh/m²/d34°7.9°F98.2°F$0.144/kWh
Kentucky (Louisville)4A4.49 kWh/m²/d34°11.8°F91°F$0.131/kWh
Louisiana (New Orleans)2A4.89 kWh/m²/d27°32.7°F93.4°F$0.124/kWh
Maine (Portland)6A4.28 kWh/m²/d39°-1.8°F85.1°F$0.274/kWh
Maryland (Baltimore)4A4.6 kWh/m²/d35°15.3°F92.1°F$0.178/kWh
Massachusetts (Boston)5A4.25 kWh/m²/d38°7.2°F88°F$0.298/kWh
Michigan (Detroit)5A4.15 kWh/m²/d38°4.5°F88.5°F$0.187/kWh
Minnesota (Minneapolis / St. Paul)6A4.45 kWh/m²/d40°-13.2°F88.7°F$0.157/kWh
Mississippi (Jackson)3A4.8 kWh/m²/d29°24.1°F94.3°F$0.139/kWh
Missouri (St. Louis / Kansas City)4A4.71 kWh/m²/d35°6.8°F93.9°F$0.134/kWh
Montana (Billings)6B4.88 kWh/m²/d41°-13.5°F92.8°F$0.126/kWh
Nebraska (Omaha)5A4.82 kWh/m²/d37°-4.9°F92.1°F$0.129/kWh
Nevada (Las Vegas)3B6.41 kWh/m²/d33°32.7°F108.3°F$0.162/kWh
New Hampshire (Manchester)5A4.22 kWh/m²/d39°-0.4°F87.8°F$0.267/kWh
New Jersey (Newark / Jersey City)4A4.52 kWh/m²/d37°14°F90.9°F$0.198/kWh
New Mexico (Albuquerque)4B6.38 kWh/m²/d32°18°F95.2°F$0.149/kWh
New York (New York City)4A4.41 kWh/m²/d37°15.1°F89.8°F$0.245/kWh
New York (Upstate) (Buffalo / Rochester)5A3.92 kWh/m²/d39°4.1°F85.5°F$0.215/kWh
North Carolina (Charlotte / Raleigh)3A4.95 kWh/m²/d32°20.3°F92.5°F$0.138/kWh
North Dakota (Fargo / Bismarck)74.52 kWh/m²/d42°-21.1°F88.5°F$0.121/kWh
Ohio (Columbus / Cleveland)5A4.25 kWh/m²/d36°5.2°F88.7°F$0.161/kWh
Oklahoma (Oklahoma City)3A5.28 kWh/m²/d32°14.5°F98.4°F$0.132/kWh
Oregon (Portland)4C4.12 kWh/m²/d41°23.4°F88.9°F$0.136/kWh
Pennsylvania (Philadelphia / Pittsburgh)4A4.39 kWh/m²/d36°13.6°F90.7°F$0.185/kWh
Rhode Island (Providence)5A4.31 kWh/m²/d37°8.8°F87.1°F$0.287/kWh
South Carolina (Columbia / Charleston)3A5.05 kWh/m²/d31°24.3°F95°F$0.146/kWh
South Dakota (Sioux Falls)6A4.75 kWh/m²/d39°-13°F89.8°F$0.133/kWh
Tennessee (Nashville / Memphis)4A4.72 kWh/m²/d33°14.7°F93°F$0.129/kWh
Texas (North) (Dallas / Fort Worth)3A5.35 kWh/m²/d30°22.8°F100.4°F$0.148/kWh
Texas (Central / South) (Houston / Austin / San Antonio)2A5.15 kWh/m²/d27°31.8°F96.1°F$0.148/kWh
Texas (West) (El Paso)3B6.32 kWh/m²/d29°25°F99.7°F$0.148/kWh
Utah (Salt Lake City)5B5.42 kWh/m²/d37°9.3°F96.6°F$0.119/kWh
Vermont (Burlington)6A4.1 kWh/m²/d40°-8.7°F85.8°F$0.218/kWh
Virginia (Richmond / Norfolk)4A4.78 kWh/m²/d34°17.6°F92.8°F$0.149/kWh
Washington (West) (Seattle / Tacoma)4C3.85 kWh/m²/d43°25.9°F84.9°F$0.124/kWh
Washington (East) (Spokane)5B4.55 kWh/m²/d43°4.3°F92.5°F$0.124/kWh
West Virginia (Charleston)4A4.32 kWh/m²/d35°10.9°F89.2°F$0.155/kWh
Wisconsin (Milwaukee / Madison)6A4.31 kWh/m²/d39°-6.5°F87.4°F$0.176/kWh
Wyoming (Cheyenne)6B5.51 kWh/m²/d37°-6.2°F88.5°F$0.127/kWh

Explore Interactive Calculators Using This Dataset

These deterministic calculators automatically integrate NREL solar radiation tables and ASHRAE design baselines for high-accuracy engineering modeling:

☀️ Solar Panel Output Calculator
Computes daily and annual kWh yield based on state peak sun hours and array derating.
📐 Solar Panel Tilt Calculator
Calculates seasonal optimal fixed and adjustable tilt angles by latitude.
❄️ Heat Pump Cost Calculator
Applies ASHRAE 99% winter design temperatures for thermal balance and auxiliary heat modeling.
🔥 Central AC Cost Calculator
Evaluates SEER2 cooling electricity expenses using ASHRAE 1% summer temperature bins.