{
  "schema_version": 1,
  "generated_at": "2026-08-24",
  "source": {
    "name": "Solar Radiation Data Manual for Flat-Plate and Concentrating Collectors (1961-1990 NSRDB), National Renewable Energy Laboratory, NREL/TP-463-5607 -- monthly flat-plate insolation at fixed tilt=latitude, converted 1:1 to peak sun hours/day",
    "url": "https://web.archive.org/web/19980204100202/http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/mon2/",
    "method": "Per station and month: arithmetic mean of all reported calendar-year values (1961-1990). Per state and month: arithmetic mean across every station located in that state, rounded to 1 decimal.",
    "retrieved": "2026-08-24"
  },
  "states": {
    "AK": {
      "monthly_peak_sun_hours": [1.1, 2.4, 4.1, 5.0, 4.8, 4.5, 4.2, 3.7, 3.0, 2.1, 1.2, 0.7],
      "stations": [
        {
          "city": "ANNETTE",
          "wban": "25308",
          "period": "1961-1990"
        },
        {
          "city": "YAKUTAT",
          "wban": "25339",
          "period": "1961-1990"
        },
        {
          "city": "KODIAK",
          "wban": "25501",
          "period": "1961-1990"
        },
        {
          "city": "KING SALMON",
          "wban": "25503",
          "period": "1961-1990"
        },
        {
          "city": "COLD BAY",
          "wban": "25624",
          "period": "1961-1990"
        },
        {
          "city": "ST PAUL IS.",
          "wban": "25713",
          "period": "1961-1990"
        },
        {
          "city": "FAIRBANKS",
          "wban": "26411",
          "period": "1961-1990"
        },
        {
          "city": "BIG DELTA",
          "wban": "26415",
          "period": "1961-1990"
        },
        {
          "city": "GULKANA",
          "wban": "26425",
          "period": "1961-1990"
        },
        {
          "city": "ANCHORAGE",
          "wban": "26451",
          "period": "1961-1990"
        },
        {
          "city": "MCGRATH",
          "wban": "26510",
          "period": "1961-1990"
        },
        {
          "city": "TALKEETNA",
          "wban": "26528",
          "period": "1961-1990"
        },
        {
          "city": "BETTLES",
          "wban": "26533",
          "period": "1961-1990"
        },
        {
          "city": "BETHEL",
          "wban": "26615",
          "period": "1961-1990"
        },
        {
          "city": "KOTZEBUE",
          "wban": "26616",
          "period": "1961-1990"
        },
        {
          "city": "NOME",
          "wban": "26617",
          "period": "1961-1990"
        },
        {
          "city": "BARROW",
          "wban": "27502",
          "period": "1961-1990"
        }
      ]
    },
    "AL": {
      "monthly_peak_sun_hours": [3.7, 4.4, 5.0, 5.6, 5.6, 5.6, 5.4, 5.5, 5.3, 5.2, 4.1, 3.5],
      "stations": [
        {
          "city": "HUNTSVILLE",
          "wban": "03856",
          "period": "1961-1990"
        },
        {
          "city": "BIRMINGHAM",
          "wban": "13876",
          "period": "1961-1990"
        },
        {
          "city": "MOBILE",
          "wban": "13894",
          "period": "1961-1990"
        },
        {
          "city": "MONTGOMERY",
          "wban": "13895",
          "period": "1961-1990"
        }
      ]
    },
    "AR": {
      "monthly_peak_sun_hours": [3.9, 4.5, 5.1, 5.6, 5.7, 5.8, 6.0, 6.0, 5.4, 5.1, 4.0, 3.6],
      "stations": [
        {
          "city": "LITTLE ROCK",
          "wban": "13963",
          "period": "1961-1990"
        },
        {
          "city": "FORT SMITH",
          "wban": "13964",
          "period": "1961-1990"
        }
      ]
    },
    "AZ": {
      "monthly_peak_sun_hours": [5.2, 5.9, 6.5, 7.1, 7.1, 7.0, 6.3, 6.5, 6.7, 6.4, 5.6, 5.0],
      "stations": [
        {
          "city": "FLAGSTAFF",
          "wban": "03103",
          "period": "1961-1990"
        },
        {
          "city": "TUCSON",
          "wban": "23160",
          "period": "1961-1990"
        },
        {
          "city": "PHOENIX",
          "wban": "23183",
          "period": "1961-1990"
        },
        {
          "city": "PRESCOTT",
          "wban": "23184",
          "period": "1961-1990"
        }
      ]
    },
    "CA": {
      "monthly_peak_sun_hours": [3.9, 4.7, 5.6, 6.4, 6.5, 6.5, 6.8, 6.7, 6.4, 5.6, 4.4, 3.8],
      "stations": [
        {
          "city": "LONG BEACH",
          "wban": "23129",
          "period": "1961-1990"
        },
        {
          "city": "BAKERSFIELD",
          "wban": "23155",
          "period": "1961-1990"
        },
        {
          "city": "DAGGETT",
          "wban": "23161",
          "period": "1961-1990"
        },
        {
          "city": "LOS ANGELES",
          "wban": "23174",
          "period": "1961-1990"
        },
        {
          "city": "SAN DIEGO",
          "wban": "23188",
          "period": "1961-1990"
        },
        {
          "city": "SACRAMENTO",
          "wban": "23232",
          "period": "1961-1990"
        },
        {
          "city": "SAN FRANCISCO",
          "wban": "23234",
          "period": "1961-1990"
        },
        {
          "city": "SANTA MARIA",
          "wban": "23273",
          "period": "1961-1990"
        },
        {
          "city": "ARCATA",
          "wban": "24283",
          "period": "1961-1990"
        },
        {
          "city": "FRESNO",
          "wban": "93193",
          "period": "1961-1990"
        }
      ]
    },
    "CO": {
      "monthly_peak_sun_hours": [4.7, 5.4, 5.8, 6.3, 6.2, 6.5, 6.4, 6.4, 6.3, 5.9, 4.8, 4.4],
      "stations": [
        {
          "city": "ALAMOSA",
          "wban": "23061",
          "period": "1961-1990"
        },
        {
          "city": "EAGLE",
          "wban": "23063",
          "period": "1961-1988"
        },
        {
          "city": "GRAND JUNCTION",
          "wban": "23066",
          "period": "1961-1990"
        },
        {
          "city": "COLORADO SPRINGS",
          "wban": "93037",
          "period": "1961-1990"
        },
        {
          "city": "PUEBLO",
          "wban": "93058",
          "period": "1961-1990"
        },
        {
          "city": "BOULDER",
          "wban": "94018",
          "period": "1961-1990"
        }
      ]
    },
    "CT": {
      "monthly_peak_sun_hours": [3.3, 4.0, 4.6, 5.0, 5.2, 5.3, 5.4, 5.3, 4.9, 4.2, 3.0, 2.7],
      "stations": [
        {
          "city": "HARTFORD",
          "wban": "14740",
          "period": "1961-1990"
        },
        {
          "city": "BRIDGEPORT",
          "wban": "94702",
          "period": "1961-1990"
        }
      ]
    },
    "DC": {
      "monthly_peak_sun_hours": [3.6, 4.2, 4.9, 5.3, 5.4, 5.6, 5.5, 5.5, 5.2, 4.7, 3.8, 3.1],
      "stations": [],
      "derived_from": [
        {
          "state": "MD",
          "city": "BALTIMORE",
          "wban": "93721"
        },
        {
          "state": "VA",
          "city": "STERLING",
          "wban": "93738"
        }
      ]
    },
    "DE": {
      "monthly_peak_sun_hours": [3.4, 4.2, 4.8, 5.2, 5.3, 5.6, 5.6, 5.5, 5.1, 4.5, 3.5, 3.0],
      "stations": [
        {
          "city": "WILMINGTON",
          "wban": "13781",
          "period": "1961-1990"
        }
      ]
    },
    "FL": {
      "monthly_peak_sun_hours": [4.4, 5.0, 5.7, 6.2, 5.8, 5.4, 5.4, 5.5, 5.2, 5.1, 4.6, 4.3],
      "stations": [
        {
          "city": "DAYTONA BEACH",
          "wban": "12834",
          "period": "1961-1990"
        },
        {
          "city": "KEY WEST",
          "wban": "12836",
          "period": "1961-1990"
        },
        {
          "city": "MIAMI",
          "wban": "12839",
          "period": "1961-1990"
        },
        {
          "city": "TAMPA",
          "wban": "12842",
          "period": "1961-1990"
        },
        {
          "city": "WEST PALM BEACH",
          "wban": "12844",
          "period": "1961-1990"
        },
        {
          "city": "JACKSONVILLE",
          "wban": "13889",
          "period": "1961-1990"
        },
        {
          "city": "TALLAHASSEE",
          "wban": "93805",
          "period": "1961-1990"
        }
      ]
    },
    "GA": {
      "monthly_peak_sun_hours": [3.9, 4.6, 5.3, 5.9, 5.8, 5.7, 5.6, 5.6, 5.3, 5.2, 4.3, 3.8],
      "stations": [
        {
          "city": "MACON",
          "wban": "03813",
          "period": "1961-1990"
        },
        {
          "city": "AUGUSTA",
          "wban": "03820",
          "period": "1961-1990"
        },
        {
          "city": "SAVANNAH",
          "wban": "03822",
          "period": "1961-1990"
        },
        {
          "city": "ATHENS",
          "wban": "13873",
          "period": "1961-1990"
        },
        {
          "city": "ATLANTA",
          "wban": "13874",
          "period": "1961-1990"
        },
        {
          "city": "COLUMBUS",
          "wban": "93842",
          "period": "1961-1990"
        }
      ]
    },
    "HI": {
      "monthly_peak_sun_hours": [4.8, 5.3, 5.4, 5.4, 5.6, 5.6, 5.6, 5.8, 5.9, 5.4, 4.8, 4.6],
      "stations": [
        {
          "city": "HILO",
          "wban": "21504",
          "period": "1961-1990"
        },
        {
          "city": "KAHULUI",
          "wban": "22516",
          "period": "1961-1990"
        },
        {
          "city": "HONOLULU",
          "wban": "22521",
          "period": "1961-1990"
        },
        {
          "city": "LIHUE",
          "wban": "22536",
          "period": "1961-1990"
        }
      ]
    },
    "IA": {
      "monthly_peak_sun_hours": [3.5, 4.3, 4.7, 5.1, 5.5, 5.8, 5.9, 5.7, 5.2, 4.5, 3.2, 2.9],
      "stations": [
        {
          "city": "DES MOINES",
          "wban": "14933",
          "period": "1961-1990"
        },
        {
          "city": "MASON CITY",
          "wban": "14940",
          "period": "1961-1990"
        },
        {
          "city": "SIOUX CITY",
          "wban": "14943",
          "period": "1961-1990"
        },
        {
          "city": "WATERLOO",
          "wban": "94910",
          "period": "1961-1990"
        }
      ]
    },
    "ID": {
      "monthly_peak_sun_hours": [2.8, 3.9, 4.9, 5.6, 6.0, 6.3, 6.8, 6.7, 6.3, 5.3, 3.2, 2.6],
      "stations": [
        {
          "city": "BOISE",
          "wban": "24131",
          "period": "1961-1990"
        },
        {
          "city": "POCATELLO",
          "wban": "24156",
          "period": "1961-1990"
        }
      ]
    },
    "IL": {
      "monthly_peak_sun_hours": [3.3, 4.1, 4.4, 5.0, 5.5, 5.7, 5.8, 5.6, 5.1, 4.4, 3.1, 2.7],
      "stations": [
        {
          "city": "PEORIA",
          "wban": "14842",
          "period": "1961-1990"
        },
        {
          "city": "MOLINE",
          "wban": "14923",
          "period": "1961-1990"
        },
        {
          "city": "SPRINGFIELD",
          "wban": "93822",
          "period": "1961-1990"
        },
        {
          "city": "ROCKFORD",
          "wban": "94822",
          "period": "1961-1990"
        },
        {
          "city": "CHICAGO",
          "wban": "94846",
          "period": "1961-1990"
        }
      ]
    },
    "IN": {
      "monthly_peak_sun_hours": [3.0, 3.8, 4.3, 5.0, 5.5, 5.7, 5.7, 5.6, 5.1, 4.3, 2.9, 2.4],
      "stations": [
        {
          "city": "FORT WAYNE",
          "wban": "14827",
          "period": "1961-1990"
        },
        {
          "city": "SOUTH BEND",
          "wban": "14848",
          "period": "1961-1990"
        },
        {
          "city": "EVANSVILLE",
          "wban": "93817",
          "period": "1961-1990"
        },
        {
          "city": "INDIANAPOLIS",
          "wban": "93819",
          "period": "1961-1990"
        }
      ]
    },
    "KS": {
      "monthly_peak_sun_hours": [4.3, 4.9, 5.4, 5.8, 5.8, 6.1, 6.3, 6.2, 5.8, 5.3, 4.3, 3.9],
      "stations": [
        {
          "city": "WICHITA",
          "wban": "03928",
          "period": "1961-1990"
        },
        {
          "city": "DODGE CITY",
          "wban": "13985",
          "period": "1961-1990"
        },
        {
          "city": "TOPEKA",
          "wban": "13996",
          "period": "1961-1990"
        },
        {
          "city": "GOODLAND",
          "wban": "23065",
          "period": "1961-1990"
        }
      ]
    },
    "KY": {
      "monthly_peak_sun_hours": [3.1, 3.8, 4.4, 5.1, 5.4, 5.6, 5.5, 5.6, 5.1, 4.6, 3.2, 2.7],
      "stations": [
        {
          "city": "COVINGTON",
          "wban": "93814",
          "period": "1961-1990"
        },
        {
          "city": "LEXINGTON",
          "wban": "93820",
          "period": "1961-1990"
        },
        {
          "city": "LOUISVILLE",
          "wban": "93821",
          "period": "1961-1990"
        }
      ]
    },
    "LA": {
      "monthly_peak_sun_hours": [3.7, 4.5, 5.0, 5.5, 5.6, 5.6, 5.5, 5.6, 5.4, 5.3, 4.2, 3.6],
      "stations": [
        {
          "city": "LAKE CHARLES",
          "wban": "03937",
          "period": "1961-1990"
        },
        {
          "city": "NEW ORLEANS",
          "wban": "12916",
          "period": "1961-1990"
        },
        {
          "city": "SHREVEPORT",
          "wban": "13957",
          "period": "1961-1990"
        },
        {
          "city": "BATON ROUGE",
          "wban": "13970",
          "period": "1961-1990"
        }
      ]
    },
    "MA": {
      "monthly_peak_sun_hours": [3.4, 4.2, 4.8, 5.0, 5.3, 5.4, 5.5, 5.4, 5.0, 4.3, 3.1, 2.8],
      "stations": [
        {
          "city": "BOSTON",
          "wban": "14739",
          "period": "1961-1990"
        },
        {
          "city": "WORCHESTER",
          "wban": "94746",
          "period": "1961-1990"
        }
      ]
    },
    "MD": {
      "monthly_peak_sun_hours": [3.5, 4.2, 4.8, 5.2, 5.3, 5.6, 5.5, 5.4, 5.1, 4.5, 3.6, 3.0],
      "stations": [
        {
          "city": "BALTIMORE",
          "wban": "93721",
          "period": "1961-1990"
        }
      ]
    },
    "ME": {
      "monthly_peak_sun_hours": [3.4, 4.4, 5.1, 5.1, 5.1, 5.3, 5.4, 5.2, 4.7, 3.8, 2.7, 2.8],
      "stations": [
        {
          "city": "CARIBOU",
          "wban": "14607",
          "period": "1961-1990"
        },
        {
          "city": "PORTLAND",
          "wban": "14764",
          "period": "1961-1990"
        }
      ]
    },
    "MI": {
      "monthly_peak_sun_hours": [2.5, 3.6, 4.5, 5.0, 5.4, 5.6, 5.7, 5.3, 4.6, 3.6, 2.3, 2.0],
      "stations": [
        {
          "city": "FLINT",
          "wban": "14826",
          "period": "1961-1990"
        },
        {
          "city": "LANSING",
          "wban": "14836",
          "period": "1961-1990"
        },
        {
          "city": "MUSKEGON",
          "wban": "14840",
          "period": "1961-1990"
        },
        {
          "city": "SAULT STE. MARIE",
          "wban": "14847",
          "period": "1961-1990"
        },
        {
          "city": "TRAVERSE CITY",
          "wban": "14850",
          "period": "1961-1990"
        },
        {
          "city": "HOUGHTON",
          "wban": "94814",
          "period": "1961-1990"
        },
        {
          "city": "DETROIT",
          "wban": "94847",
          "period": "1961-1990"
        },
        {
          "city": "ALPENA",
          "wban": "94849",
          "period": "1961-1990"
        },
        {
          "city": "GRAND RAPIDS",
          "wban": "94860",
          "period": "1961-1990"
        }
      ]
    },
    "MN": {
      "monthly_peak_sun_hours": [3.3, 4.4, 5.0, 5.2, 5.4, 5.5, 5.7, 5.4, 4.7, 3.8, 2.7, 2.6],
      "stations": [
        {
          "city": "DULUTH",
          "wban": "14913",
          "period": "1961-1990"
        },
        {
          "city": "INTERNATIONAL FALLS",
          "wban": "14918",
          "period": "1961-1990"
        },
        {
          "city": "MINNEAPOLIS",
          "wban": "14922",
          "period": "1961-1990"
        },
        {
          "city": "ROCHESTER",
          "wban": "14925",
          "period": "1961-1990"
        },
        {
          "city": "SAINT CLOUD",
          "wban": "14926",
          "period": "1961-1990"
        }
      ]
    },
    "MO": {
      "monthly_peak_sun_hours": [3.8, 4.3, 4.8, 5.4, 5.6, 5.8, 6.0, 5.9, 5.4, 4.9, 3.7, 3.2],
      "stations": [
        {
          "city": "COLUMBIA",
          "wban": "03945",
          "period": "1961-1990"
        },
        {
          "city": "KANSAS CITY",
          "wban": "03947",
          "period": "1961-1990"
        },
        {
          "city": "ST. LOUIS",
          "wban": "13994",
          "period": "1961-1990"
        },
        {
          "city": "SPRINGFIELD",
          "wban": "13995",
          "period": "1961-1990"
        }
      ]
    },
    "MS": {
      "monthly_peak_sun_hours": [3.7, 4.5, 5.1, 5.6, 5.7, 5.7, 5.5, 5.6, 5.4, 5.2, 4.2, 3.6],
      "stations": [
        {
          "city": "JACKSON",
          "wban": "03940",
          "period": "1961-1990"
        },
        {
          "city": "MERIDIAN",
          "wban": "13865",
          "period": "1961-1990"
        }
      ]
    },
    "MT": {
      "monthly_peak_sun_hours": [2.9, 3.9, 4.8, 5.3, 5.5, 5.8, 6.4, 6.2, 5.5, 4.5, 3.0, 2.5],
      "stations": [
        {
          "city": "BILLINGS",
          "wban": "24033",
          "period": "1961-1990"
        },
        {
          "city": "LEWISTOWN",
          "wban": "24036",
          "period": "1961-1990"
        },
        {
          "city": "MILES CITY",
          "wban": "24037",
          "period": "1961-1989"
        },
        {
          "city": "CUT BANK",
          "wban": "24137",
          "period": "1961-1988"
        },
        {
          "city": "GREAT FALLS",
          "wban": "24143",
          "period": "1961-1990"
        },
        {
          "city": "HELENA",
          "wban": "24144",
          "period": "1961-1990"
        },
        {
          "city": "KALISPELL",
          "wban": "24146",
          "period": "1961-1990"
        },
        {
          "city": "MISSOULA",
          "wban": "24153",
          "period": "1961-1990"
        },
        {
          "city": "GLASGOW",
          "wban": "94008",
          "period": "1961-1990"
        }
      ]
    },
    "NC": {
      "monthly_peak_sun_hours": [3.9, 4.5, 5.2, 5.8, 5.7, 5.6, 5.5, 5.5, 5.2, 5.0, 4.2, 3.6],
      "stations": [
        {
          "city": "ASHEVILLE",
          "wban": "03812",
          "period": "1961-1990"
        },
        {
          "city": "RALEIGH",
          "wban": "13722",
          "period": "1961-1990"
        },
        {
          "city": "GREENSBORO",
          "wban": "13723",
          "period": "1961-1990"
        },
        {
          "city": "WILMINGTON",
          "wban": "13748",
          "period": "1961-1990"
        },
        {
          "city": "CHARLOTTE",
          "wban": "13881",
          "period": "1961-1990"
        },
        {
          "city": "CAPE HATTERAS",
          "wban": "93729",
          "period": "1961-1990"
        }
      ]
    },
    "ND": {
      "monthly_peak_sun_hours": [3.4, 4.3, 5.1, 5.4, 5.6, 5.8, 6.2, 6.0, 5.1, 4.3, 3.1, 2.8],
      "stations": [
        {
          "city": "FARGO",
          "wban": "14914",
          "period": "1961-1990"
        },
        {
          "city": "BISMARCK",
          "wban": "24011",
          "period": "1961-1990"
        },
        {
          "city": "MINOT",
          "wban": "24013",
          "period": "1961-1988"
        }
      ]
    },
    "NE": {
      "monthly_peak_sun_hours": [4.0, 4.6, 5.2, 5.6, 5.7, 6.1, 6.2, 6.1, 5.6, 5.0, 3.9, 3.5],
      "stations": [
        {
          "city": "GRAND ISLAND",
          "wban": "14935",
          "period": "1961-1990"
        },
        {
          "city": "NORFOLK",
          "wban": "14941",
          "period": "1961-1990"
        },
        {
          "city": "NORTH PLATTE",
          "wban": "24023",
          "period": "1961-1990"
        },
        {
          "city": "SCOTTSBLUFF",
          "wban": "24028",
          "period": "1961-1990"
        },
        {
          "city": "OMAHA",
          "wban": "94918",
          "period": "1961-1990"
        }
      ]
    },
    "NH": {
      "monthly_peak_sun_hours": [3.5, 4.5, 5.0, 5.1, 5.3, 5.5, 5.6, 5.5, 5.0, 4.2, 3.0, 2.8],
      "stations": [
        {
          "city": "CONCORD",
          "wban": "14745",
          "period": "1961-1990"
        }
      ]
    },
    "NJ": {
      "monthly_peak_sun_hours": [3.4, 4.1, 4.7, 5.1, 5.3, 5.4, 5.4, 5.4, 5.0, 4.5, 3.4, 2.9],
      "stations": [
        {
          "city": "NEWARK",
          "wban": "14734",
          "period": "1961-1990"
        },
        {
          "city": "ATLANTIC CITY",
          "wban": "93730",
          "period": "1961-1990"
        }
      ]
    },
    "NM": {
      "monthly_peak_sun_hours": [5.2, 5.8, 6.4, 6.9, 6.9, 6.9, 6.7, 6.7, 6.5, 6.3, 5.4, 4.9],
      "stations": [
        {
          "city": "TUCUMCARI",
          "wban": "23048",
          "period": "1961-1988"
        },
        {
          "city": "ALBUQUERQUE",
          "wban": "23050",
          "period": "1961-1990"
        }
      ]
    },
    "NV": {
      "monthly_peak_sun_hours": [4.4, 5.1, 5.8, 6.3, 6.5, 6.8, 7.0, 6.9, 6.9, 6.1, 4.6, 4.1],
      "stations": [
        {
          "city": "TONOPAH",
          "wban": "23153",
          "period": "1961-1990"
        },
        {
          "city": "ELY",
          "wban": "23154",
          "period": "1961-1990"
        },
        {
          "city": "LAS VEGAS",
          "wban": "23169",
          "period": "1961-1990"
        },
        {
          "city": "RENO",
          "wban": "23185",
          "period": "1961-1990"
        },
        {
          "city": "ELKO",
          "wban": "24121",
          "period": "1961-1990"
        },
        {
          "city": "WINNEMUCCA",
          "wban": "24128",
          "period": "1961-1990"
        }
      ]
    },
    "NY": {
      "monthly_peak_sun_hours": [2.8, 3.7, 4.5, 4.9, 5.2, 5.4, 5.5, 5.3, 4.7, 3.8, 2.5, 2.2],
      "stations": [
        {
          "city": "BINGHAMTON",
          "wban": "04725",
          "period": "1961-1990"
        },
        {
          "city": "BUFFALO",
          "wban": "14733",
          "period": "1961-1990"
        },
        {
          "city": "ALBANY",
          "wban": "14735",
          "period": "1961-1990"
        },
        {
          "city": "ROCHESTER",
          "wban": "14768",
          "period": "1961-1990"
        },
        {
          "city": "SYRACUSE",
          "wban": "14771",
          "period": "1961-1990"
        },
        {
          "city": "MASSENA",
          "wban": "94725",
          "period": "1961-1990"
        },
        {
          "city": "NEW YORK CITY",
          "wban": "94728",
          "period": "1961-1990"
        }
      ]
    },
    "OH": {
      "monthly_peak_sun_hours": [2.6, 3.4, 4.1, 4.8, 5.2, 5.5, 5.5, 5.3, 4.9, 4.1, 2.6, 2.1],
      "stations": [
        {
          "city": "CLEVELAND",
          "wban": "14820",
          "period": "1961-1990"
        },
        {
          "city": "COLUMBUS",
          "wban": "14821",
          "period": "1961-1990"
        },
        {
          "city": "YOUNGSTOWN",
          "wban": "14852",
          "period": "1961-1990"
        },
        {
          "city": "MANSFIELD",
          "wban": "14891",
          "period": "1961-1990"
        },
        {
          "city": "AKRON",
          "wban": "14895",
          "period": "1961-1990"
        },
        {
          "city": "DAYTON",
          "wban": "93815",
          "period": "1961-1990"
        },
        {
          "city": "TOLEDO",
          "wban": "94830",
          "period": "1961-1990"
        }
      ]
    },
    "OK": {
      "monthly_peak_sun_hours": [4.2, 4.7, 5.3, 5.7, 5.7, 5.9, 6.2, 6.1, 5.6, 5.2, 4.2, 3.9],
      "stations": [
        {
          "city": "OKLAHOMA CITY",
          "wban": "13967",
          "period": "1961-1990"
        },
        {
          "city": "TULSA",
          "wban": "13968",
          "period": "1961-1990"
        }
      ]
    },
    "OR": {
      "monthly_peak_sun_hours": [2.3, 3.2, 4.2, 5.1, 5.6, 5.8, 6.3, 6.2, 5.7, 4.3, 2.5, 2.0],
      "stations": [
        {
          "city": "PENDLETON",
          "wban": "24155",
          "period": "1961-1990"
        },
        {
          "city": "EUGENE",
          "wban": "24221",
          "period": "1961-1990"
        },
        {
          "city": "MEDFORD",
          "wban": "24225",
          "period": "1961-1990"
        },
        {
          "city": "PORTLAND",
          "wban": "24229",
          "period": "1961-1990"
        },
        {
          "city": "REDMOND",
          "wban": "24230",
          "period": "1961-1990"
        },
        {
          "city": "SALEM",
          "wban": "24232",
          "period": "1961-1990"
        },
        {
          "city": "NORTH BEND",
          "wban": "24284",
          "period": "1961-1990"
        },
        {
          "city": "BURNS",
          "wban": "94185",
          "period": "1961-1988"
        },
        {
          "city": "ASTORIA",
          "wban": "94224",
          "period": "1961-1990"
        }
      ]
    },
    "PA": {
      "monthly_peak_sun_hours": [2.9, 3.7, 4.4, 4.9, 5.2, 5.5, 5.5, 5.3, 4.8, 4.1, 2.8, 2.3],
      "stations": [
        {
          "city": "BRADFORD",
          "wban": "04751",
          "period": "1961-1990"
        },
        {
          "city": "PHILADELPHIA",
          "wban": "13739",
          "period": "1961-1990"
        },
        {
          "city": "ALLENTOWN",
          "wban": "14737",
          "period": "1961-1990"
        },
        {
          "city": "HARRISBURG",
          "wban": "14751",
          "period": "1961-1990"
        },
        {
          "city": "WILKES-BARRE",
          "wban": "14777",
          "period": "1961-1990"
        },
        {
          "city": "WILLIAMSPORT",
          "wban": "14778",
          "period": "1961-1990"
        },
        {
          "city": "ERIE",
          "wban": "14860",
          "period": "1961-1990"
        },
        {
          "city": "PITTSBURGH",
          "wban": "94823",
          "period": "1961-1990"
        }
      ]
    },
    "RI": {
      "monthly_peak_sun_hours": [3.4, 4.1, 4.7, 5.0, 5.3, 5.4, 5.5, 5.3, 5.0, 4.4, 3.2, 2.9],
      "stations": [
        {
          "city": "PROVIDENCE",
          "wban": "14765",
          "period": "1961-1990"
        }
      ]
    },
    "SC": {
      "monthly_peak_sun_hours": [4.0, 4.7, 5.3, 5.9, 5.7, 5.6, 5.6, 5.5, 5.2, 5.2, 4.4, 3.8],
      "stations": [
        {
          "city": "GREENVILLE",
          "wban": "03870",
          "period": "1961-1990"
        },
        {
          "city": "CHARLESTON",
          "wban": "13880",
          "period": "1961-1990"
        },
        {
          "city": "COLUMBIA",
          "wban": "13883",
          "period": "1961-1990"
        }
      ]
    },
    "SD": {
      "monthly_peak_sun_hours": [3.6, 4.3, 5.0, 5.4, 5.6, 6.0, 6.2, 6.1, 5.6, 4.8, 3.5, 3.1],
      "stations": [
        {
          "city": "HURON",
          "wban": "14936",
          "period": "1961-1990"
        },
        {
          "city": "SIOUX FALLS",
          "wban": "14944",
          "period": "1961-1990"
        },
        {
          "city": "PIERRE",
          "wban": "24025",
          "period": "1961-1990"
        },
        {
          "city": "RAPID CITY",
          "wban": "24090",
          "period": "1961-1990"
        }
      ]
    },
    "TN": {
      "monthly_peak_sun_hours": [3.5, 4.1, 4.8, 5.5, 5.5, 5.7, 5.6, 5.6, 5.2, 4.9, 3.7, 3.2],
      "stations": [
        {
          "city": "BRISTOL",
          "wban": "13877",
          "period": "1961-1990"
        },
        {
          "city": "CHATTANOOGA",
          "wban": "13882",
          "period": "1961-1990"
        },
        {
          "city": "KNOXVILLE",
          "wban": "13891",
          "period": "1961-1990"
        },
        {
          "city": "MEMPHIS",
          "wban": "13893",
          "period": "1961-1990"
        },
        {
          "city": "NASHVILLE",
          "wban": "13897",
          "period": "1961-1990"
        }
      ]
    },
    "TX": {
      "monthly_peak_sun_hours": [4.3, 5.0, 5.6, 5.8, 5.8, 6.0, 6.1, 6.1, 5.8, 5.6, 4.7, 4.1],
      "stations": [
        {
          "city": "FORT WORTH",
          "wban": "03927",
          "period": "1961-1990"
        },
        {
          "city": "VICTORIA",
          "wban": "12912",
          "period": "1961-1990"
        },
        {
          "city": "PORT ARTHUR",
          "wban": "12917",
          "period": "1961-1990"
        },
        {
          "city": "BROWNSVILLE",
          "wban": "12919",
          "period": "1961-1990"
        },
        {
          "city": "SAN ANTONIO",
          "wban": "12921",
          "period": "1961-1990"
        },
        {
          "city": "CORPUS CHRISTI",
          "wban": "12924",
          "period": "1961-1990"
        },
        {
          "city": "HOUSTON",
          "wban": "12960",
          "period": "1961-1990"
        },
        {
          "city": "AUSTIN",
          "wban": "13958",
          "period": "1961-1990"
        },
        {
          "city": "WACO",
          "wban": "13959",
          "period": "1961-1990"
        },
        {
          "city": "ABLIENE",
          "wban": "13962",
          "period": "1961-1990"
        },
        {
          "city": "WICHITA FALLS",
          "wban": "13966",
          "period": "1961-1990"
        },
        {
          "city": "MIDLAND",
          "wban": "23023",
          "period": "1961-1990"
        },
        {
          "city": "SAN ANGELO",
          "wban": "23034",
          "period": "1961-1990"
        },
        {
          "city": "LUBBOCK",
          "wban": "23042",
          "period": "1961-1990"
        },
        {
          "city": "EL PASO",
          "wban": "23044",
          "period": "1961-1990"
        },
        {
          "city": "AMARILLO",
          "wban": "23047",
          "period": "1961-1990"
        },
        {
          "city": "LUFKIN",
          "wban": "93987",
          "period": "1961-1990"
        }
      ]
    },
    "UT": {
      "monthly_peak_sun_hours": [3.9, 4.7, 5.5, 6.1, 6.3, 6.7, 6.6, 6.6, 6.6, 5.8, 4.3, 3.6],
      "stations": [
        {
          "city": "SALT LAKE CITY",
          "wban": "24127",
          "period": "1961-1990"
        },
        {
          "city": "CEDAR CITY",
          "wban": "93129",
          "period": "1961-1990"
        }
      ]
    },
    "VA": {
      "monthly_peak_sun_hours": [3.7, 4.3, 5.0, 5.4, 5.5, 5.6, 5.5, 5.5, 5.2, 4.8, 3.9, 3.3],
      "stations": [
        {
          "city": "LYNCHBURG",
          "wban": "13733",
          "period": "1961-1990"
        },
        {
          "city": "NORFOLK",
          "wban": "13737",
          "period": "1961-1990"
        },
        {
          "city": "RICHMOND",
          "wban": "13740",
          "period": "1961-1990"
        },
        {
          "city": "ROANOKE",
          "wban": "13741",
          "period": "1961-1990"
        },
        {
          "city": "STERLING",
          "wban": "93738",
          "period": "1961-1990"
        }
      ]
    },
    "VT": {
      "monthly_peak_sun_hours": [2.9, 3.9, 4.7, 4.9, 5.2, 5.4, 5.6, 5.3, 4.8, 3.7, 2.4, 2.1],
      "stations": [
        {
          "city": "BURLINGTON",
          "wban": "14742",
          "period": "1961-1990"
        }
      ]
    },
    "WA": {
      "monthly_peak_sun_hours": [1.9, 2.8, 3.9, 4.7, 5.2, 5.4, 5.8, 5.7, 5.1, 3.7, 2.1, 1.7],
      "stations": [
        {
          "city": "SPOKANE",
          "wban": "24157",
          "period": "1961-1990"
        },
        {
          "city": "OLYMPIA",
          "wban": "24227",
          "period": "1961-1990"
        },
        {
          "city": "SEATTLE",
          "wban": "24233",
          "period": "1961-1990"
        },
        {
          "city": "YAKIMA",
          "wban": "24243",
          "period": "1961-1990"
        },
        {
          "city": "QUILLAYUTE",
          "wban": "94240",
          "period": "1961-1990"
        }
      ]
    },
    "WI": {
      "monthly_peak_sun_hours": [3.3, 4.2, 4.7, 5.0, 5.4, 5.6, 5.7, 5.5, 4.8, 4.0, 2.7, 2.6],
      "stations": [
        {
          "city": "MADISON",
          "wban": "14837",
          "period": "1961-1990"
        },
        {
          "city": "MILWAUKEE",
          "wban": "14839",
          "period": "1961-1990"
        },
        {
          "city": "GREEN BAY",
          "wban": "14898",
          "period": "1961-1990"
        },
        {
          "city": "LA CROSSE",
          "wban": "14920",
          "period": "1961-1990"
        },
        {
          "city": "EAU CLAIRE",
          "wban": "14991",
          "period": "1961-1990"
        }
      ]
    },
    "WV": {
      "monthly_peak_sun_hours": [2.9, 3.6, 4.3, 4.9, 5.2, 5.3, 5.3, 5.2, 4.8, 4.3, 3.1, 2.5],
      "stations": [
        {
          "city": "HUNTINGTON",
          "wban": "03860",
          "period": "1961-1990"
        },
        {
          "city": "ELKINS",
          "wban": "13729",
          "period": "1961-1990"
        },
        {
          "city": "CHARLESTON",
          "wban": "13866",
          "period": "1961-1990"
        }
      ]
    },
    "WY": {
      "monthly_peak_sun_hours": [4.0, 4.8, 5.5, 5.8, 5.8, 6.2, 6.4, 6.4, 6.1, 5.3, 4.1, 3.7],
      "stations": [
        {
          "city": "CHEYENNE",
          "wban": "24018",
          "period": "1961-1990"
        },
        {
          "city": "LANDER",
          "wban": "24021",
          "period": "1961-1990"
        },
        {
          "city": "ROCK SPRINGS",
          "wban": "24027",
          "period": "1961-1990"
        },
        {
          "city": "SHERIDAN",
          "wban": "24029",
          "period": "1961-1990"
        },
        {
          "city": "CASPER",
          "wban": "24089",
          "period": "1961-1990"
        }
      ]
    }
  },
  "meta": {
    "title": "Monthly peak sun hours by US state",
    "generated_for": "balcony-solar-tzhy.3 (simulator location selector)",
    "units": "peak sun hours per day (equivalent to kWh/m^2/day)",
    "months": ["Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"],
    "citation": {
      "publisher": "National Renewable Energy Laboratory",
      "publication_number": "NREL/TP-463-5607",
      "value_basis_column": "Flat-Plate Collector Facing South at Fixed Tilt=Latitude (monthly kWh/m^2/day, COLUMN E of the mon2 station files)",
      "dataset_url_template": "https://web.archive.org/web/<snapshot>/http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/mon2/<WBAN>.txt"
    },
    "station_count": 237,
    "excluded_territories": ["PR", "PI"],
    "substitutions": [
      {
        "state": "DC",
        "reason": "No NSRDB 1961-1990 station lies within the District of Columbia; DC is the arithmetic mean of the two nearest stations.",
        "stations": [
          {
            "state": "MD",
            "city": "BALTIMORE",
            "wban": "93721"
          },
          {
            "state": "VA",
            "city": "STERLING",
            "wban": "93738"
          }
        ]
      }
    ],
    "notes": [
      "Peak sun hours = daily insolation (kWh/m^2) divided by one sun (1 kW/m^2).",
      "Values are 1961-1990 climatological normals; they are the classic PVWatts-era basis and differ slightly from newer NSRDB datasets.",
      "State-level averages smooth elevation and microclimate variation (e.g. coastal vs inland); metro refinement is deferred by balcony-solar-tzhy.3.",
      "Real balcony arrays are often near-vertical or partially shaded; treat these latitude-tilt figures as a site-quality reference, not a production guarantee."
    ]
  }
}