{
  "name": "USDA Zones & Frost Dates by US State — open table",
  "description": "Open reference table for all US states: the USDA hardiness zone range, the dominant half-zone, average last spring and first fall frost, census region, and the coldest and warmest area characterization. Free CSV + JSON, CC-BY 4.0.",
  "url": "https://www.getgrowli.app/data/us-state-zones-frost",
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "creditText": "US-state hardiness-zone and frost-date reference table compiled by Growli (getgrowli.app), CC-BY 4.0, from the USDA Plant Hardiness Zone Map (2023) and NOAA climate normals.",
  "sources": [
    "USDA Plant Hardiness Zone Map, 2023 revision (planthardiness.ars.usda.gov)",
    "NOAA Climate Data Online — 1991–2020 climate normals (ncei.noaa.gov)"
  ],
  "methodology": "Zone ranges and dominant half-zones are read from the USDA Plant Hardiness Zone Map 2023 revision. Frost dates are populated-area state averages derived from NOAA 1991–2020 climate normals; a single state can span several zones, so the coldest- and warmest-area columns flag that internal range. State-level figures are for orientation — local dates vary by ZIP code.",
  "spatialCoverage": "US",
  "lastVerified": "2026-05-15",
  "recordCount": 51,
  "data": [
    {
      "state": "Alabama",
      "abbr": "AL",
      "region": "Southeast",
      "zoneRange": "7a-9a",
      "dominantZone": "8a",
      "lastFrost": "late March",
      "firstFrost": "early November",
      "coldestArea": "the northern Appalachian foothills (zone 7a)",
      "warmestArea": "the Gulf Coast around Mobile (zone 9a)"
    },
    {
      "state": "Alaska",
      "abbr": "AK",
      "region": "Pacific",
      "zoneRange": "1a-8b",
      "dominantZone": "4b",
      "lastFrost": "late May",
      "firstFrost": "mid-September",
      "coldestArea": "the interior near Fairbanks (zone 1a-2b)",
      "warmestArea": "the southeast coast and panhandle around Sitka (zone 8b)"
    },
    {
      "state": "Arizona",
      "abbr": "AZ",
      "region": "Southwest",
      "zoneRange": "4b-10b",
      "dominantZone": "9a",
      "lastFrost": "mid-February (low desert)",
      "firstFrost": "early December (low desert)",
      "coldestArea": "the high country around Flagstaff (zone 4b-6a)",
      "warmestArea": "the low desert around Yuma and Phoenix (zone 10b)"
    },
    {
      "state": "Arkansas",
      "abbr": "AR",
      "region": "Southeast",
      "zoneRange": "6b-8a",
      "dominantZone": "7b",
      "lastFrost": "early April",
      "firstFrost": "late October",
      "coldestArea": "the Ozark and Ouachita highlands (zone 6b)",
      "warmestArea": "the southern and Delta lowlands near Little Rock (zone 8a)"
    },
    {
      "state": "California",
      "abbr": "CA",
      "region": "Pacific",
      "zoneRange": "5a-11a",
      "dominantZone": "9b",
      "lastFrost": "mid-February (coast) to late April (interior)",
      "firstFrost": "mid-November (coast) to mid-October (interior)",
      "coldestArea": "the high Sierra Nevada (zone 5a-6a)",
      "warmestArea": "the southern coast and Imperial Valley (zone 11a)"
    },
    {
      "state": "Colorado",
      "abbr": "CO",
      "region": "West",
      "zoneRange": "3b-7a",
      "dominantZone": "5b",
      "lastFrost": "mid-May",
      "firstFrost": "late September",
      "coldestArea": "the high Rockies and mountain valleys (zone 3b-4b)",
      "warmestArea": "the western slope around Grand Junction (zone 7a)"
    },
    {
      "state": "Connecticut",
      "abbr": "CT",
      "region": "Northeast",
      "zoneRange": "5b-7b",
      "dominantZone": "6b",
      "lastFrost": "late April",
      "firstFrost": "mid-October",
      "coldestArea": "the northwest hills near Litchfield (zone 5b)",
      "warmestArea": "the Long Island Sound shoreline (zone 7b)"
    },
    {
      "state": "Delaware",
      "abbr": "DE",
      "region": "Northeast",
      "zoneRange": "7a-8a",
      "dominantZone": "7b",
      "lastFrost": "mid-April",
      "firstFrost": "late October",
      "coldestArea": "the northern Piedmont near Wilmington (zone 7a)",
      "warmestArea": "the Atlantic coast and lower Delmarva (zone 8a)"
    },
    {
      "state": "Florida",
      "abbr": "FL",
      "region": "Southeast",
      "zoneRange": "8a-11b",
      "dominantZone": "9b",
      "lastFrost": "late February (north) to no frost (south)",
      "firstFrost": "mid-December (north) to no frost (south)",
      "coldestArea": "the western Panhandle near Tallahassee (zone 8a)",
      "warmestArea": "the Florida Keys (zone 11b)"
    },
    {
      "state": "Georgia",
      "abbr": "GA",
      "region": "Southeast",
      "zoneRange": "6b-9a",
      "dominantZone": "8a",
      "lastFrost": "early April",
      "firstFrost": "early November",
      "coldestArea": "the Blue Ridge mountains in the north (zone 6b)",
      "warmestArea": "the Atlantic coast around Savannah (zone 9a)"
    },
    {
      "state": "Hawaii",
      "abbr": "HI",
      "region": "Pacific",
      "zoneRange": "9a-13a",
      "dominantZone": "12b",
      "lastFrost": "no frost",
      "firstFrost": "no frost",
      "coldestArea": "the upper slopes of Mauna Kea and Haleakala (zone 9a)",
      "warmestArea": "the coastal lowlands of all islands (zone 13a)"
    },
    {
      "state": "Idaho",
      "abbr": "ID",
      "region": "West",
      "zoneRange": "3a-7a",
      "dominantZone": "6a",
      "lastFrost": "mid-May",
      "firstFrost": "late September",
      "coldestArea": "the central mountains and high valleys (zone 3a-4b)",
      "warmestArea": "the Treasure Valley around Boise (zone 7a)"
    },
    {
      "state": "Illinois",
      "abbr": "IL",
      "region": "Midwest",
      "zoneRange": "5a-7a",
      "dominantZone": "6a",
      "lastFrost": "late April",
      "firstFrost": "mid-October",
      "coldestArea": "the northern counties near the Wisconsin line (zone 5a)",
      "warmestArea": "the far south near Cairo and Carbondale (zone 7a)"
    },
    {
      "state": "Indiana",
      "abbr": "IN",
      "region": "Midwest",
      "zoneRange": "5b-7a",
      "dominantZone": "6a",
      "lastFrost": "late April",
      "firstFrost": "mid-October",
      "coldestArea": "the northern lake-effect counties (zone 5b)",
      "warmestArea": "the Ohio River valley near Evansville (zone 7a)"
    },
    {
      "state": "Iowa",
      "abbr": "IA",
      "region": "Midwest",
      "zoneRange": "4b-6a",
      "dominantZone": "5b",
      "lastFrost": "late April",
      "firstFrost": "early October",
      "coldestArea": "the northern counties near Minnesota (zone 4b)",
      "warmestArea": "the southeast along the Mississippi (zone 6a)"
    },
    {
      "state": "Kansas",
      "abbr": "KS",
      "region": "Midwest",
      "zoneRange": "5b-7a",
      "dominantZone": "6b",
      "lastFrost": "mid-April",
      "firstFrost": "late October",
      "coldestArea": "the northwest High Plains (zone 5b)",
      "warmestArea": "the south-central plains around Wichita (zone 7a)"
    },
    {
      "state": "Kentucky",
      "abbr": "KY",
      "region": "Southeast",
      "zoneRange": "6a-7b",
      "dominantZone": "6b",
      "lastFrost": "mid-April",
      "firstFrost": "mid-October",
      "coldestArea": "the eastern Appalachian highlands (zone 6a)",
      "warmestArea": "the Ohio River valley around Louisville (zone 7b)"
    },
    {
      "state": "Louisiana",
      "abbr": "LA",
      "region": "Southeast",
      "zoneRange": "8a-9b",
      "dominantZone": "9a",
      "lastFrost": "mid-March",
      "firstFrost": "mid-November",
      "coldestArea": "the northern parishes near Shreveport (zone 8a)",
      "warmestArea": "the Gulf Coast and New Orleans (zone 9b)"
    },
    {
      "state": "Maine",
      "abbr": "ME",
      "region": "Northeast",
      "zoneRange": "3b-6a",
      "dominantZone": "5a",
      "lastFrost": "mid-May",
      "firstFrost": "late September",
      "coldestArea": "the far north Aroostook County interior (zone 3b)",
      "warmestArea": "the southern coast around Portland (zone 6a)"
    },
    {
      "state": "Maryland",
      "abbr": "MD",
      "region": "Northeast",
      "zoneRange": "6a-8a",
      "dominantZone": "7b",
      "lastFrost": "mid-April",
      "firstFrost": "late October",
      "coldestArea": "the western Appalachian panhandle near Oakland (zone 6a)",
      "warmestArea": "the Chesapeake and Atlantic shoreline (zone 8a)"
    },
    {
      "state": "Massachusetts",
      "abbr": "MA",
      "region": "Northeast",
      "zoneRange": "5b-7b",
      "dominantZone": "6b",
      "lastFrost": "late April",
      "firstFrost": "mid-October",
      "coldestArea": "the Berkshire hills in the west (zone 5b)",
      "warmestArea": "Cape Cod and the islands (zone 7b)"
    },
    {
      "state": "Michigan",
      "abbr": "MI",
      "region": "Midwest",
      "zoneRange": "4a-6b",
      "dominantZone": "6a",
      "lastFrost": "mid-May",
      "firstFrost": "early October",
      "coldestArea": "the western Upper Peninsula interior (zone 4a)",
      "warmestArea": "the southeast near Detroit and the Lake Michigan fruit belt (zone 6b)"
    },
    {
      "state": "Minnesota",
      "abbr": "MN",
      "region": "Midwest",
      "zoneRange": "3a-5a",
      "dominantZone": "4b",
      "lastFrost": "mid-May",
      "firstFrost": "late September",
      "coldestArea": "the far north near International Falls (zone 3a)",
      "warmestArea": "the Twin Cities metro and far south (zone 5a)"
    },
    {
      "state": "Mississippi",
      "abbr": "MS",
      "region": "Southeast",
      "zoneRange": "7b-9a",
      "dominantZone": "8b",
      "lastFrost": "late March",
      "firstFrost": "early November",
      "coldestArea": "the northern hill country near Tupelo (zone 7b)",
      "warmestArea": "the Gulf Coast around Gulfport (zone 9a)"
    },
    {
      "state": "Missouri",
      "abbr": "MO",
      "region": "Midwest",
      "zoneRange": "5b-7a",
      "dominantZone": "6b",
      "lastFrost": "mid-April",
      "firstFrost": "mid-October",
      "coldestArea": "the northern counties near Iowa (zone 5b)",
      "warmestArea": "the Bootheel in the southeast (zone 7a)"
    },
    {
      "state": "Montana",
      "abbr": "MT",
      "region": "West",
      "zoneRange": "3a-6a",
      "dominantZone": "4b",
      "lastFrost": "late May",
      "firstFrost": "mid-September",
      "coldestArea": "the high mountain valleys and northern plains (zone 3a)",
      "warmestArea": "the lower western valleys near Missoula (zone 6a)"
    },
    {
      "state": "Nebraska",
      "abbr": "NE",
      "region": "Midwest",
      "zoneRange": "4b-6a",
      "dominantZone": "5b",
      "lastFrost": "late April",
      "firstFrost": "early October",
      "coldestArea": "the northern Sandhills and Panhandle (zone 4b)",
      "warmestArea": "the southeast near the Missouri River (zone 6a)"
    },
    {
      "state": "Nevada",
      "abbr": "NV",
      "region": "Southwest",
      "zoneRange": "4b-10a",
      "dominantZone": "7a",
      "lastFrost": "mid-April",
      "firstFrost": "late October",
      "coldestArea": "the high northern Great Basin near Elko (zone 4b)",
      "warmestArea": "the Mojave around Las Vegas (zone 10a)"
    },
    {
      "state": "New Hampshire",
      "abbr": "NH",
      "region": "Northeast",
      "zoneRange": "3b-6a",
      "dominantZone": "5b",
      "lastFrost": "mid-May",
      "firstFrost": "late September",
      "coldestArea": "the White Mountains and far north (zone 3b)",
      "warmestArea": "the short Atlantic seacoast near Portsmouth (zone 6a)"
    },
    {
      "state": "New Jersey",
      "abbr": "NJ",
      "region": "Northeast",
      "zoneRange": "6a-7b",
      "dominantZone": "7a",
      "lastFrost": "mid-April",
      "firstFrost": "late October",
      "coldestArea": "the northwest Highlands near High Point (zone 6a)",
      "warmestArea": "the Atlantic shore and inner harbor (zone 7b)"
    },
    {
      "state": "New Mexico",
      "abbr": "NM",
      "region": "Southwest",
      "zoneRange": "4b-9a",
      "dominantZone": "7a",
      "lastFrost": "late April",
      "firstFrost": "late October",
      "coldestArea": "the high Sangre de Cristo mountains (zone 4b)",
      "warmestArea": "the southern Rio Grande and Chihuahuan desert (zone 9a)"
    },
    {
      "state": "New York",
      "abbr": "NY",
      "region": "Northeast",
      "zoneRange": "3b-7b",
      "dominantZone": "5b",
      "lastFrost": "early May (upstate) to mid-April (NYC)",
      "firstFrost": "early October (upstate) to early November (NYC)",
      "coldestArea": "the Adirondacks and Tug Hill plateau (zone 3b)",
      "warmestArea": "New York City and Long Island (zone 7b)"
    },
    {
      "state": "North Carolina",
      "abbr": "NC",
      "region": "Southeast",
      "zoneRange": "5b-8b",
      "dominantZone": "7b",
      "lastFrost": "early April",
      "firstFrost": "late October",
      "coldestArea": "the high Blue Ridge near Mount Mitchell (zone 5b)",
      "warmestArea": "the southern coast around Wilmington (zone 8b)"
    },
    {
      "state": "North Dakota",
      "abbr": "ND",
      "region": "Midwest",
      "zoneRange": "3a-4b",
      "dominantZone": "4a",
      "lastFrost": "mid-May",
      "firstFrost": "late September",
      "coldestArea": "the far north near the Canadian border (zone 3a)",
      "warmestArea": "the southern Red River and Missouri valleys (zone 4b)"
    },
    {
      "state": "Ohio",
      "abbr": "OH",
      "region": "Midwest",
      "zoneRange": "5b-6b",
      "dominantZone": "6a",
      "lastFrost": "late April",
      "firstFrost": "mid-October",
      "coldestArea": "the northeast snowbelt and Allegheny foothills (zone 5b)",
      "warmestArea": "the Ohio River valley near Cincinnati (zone 6b)"
    },
    {
      "state": "Oklahoma",
      "abbr": "OK",
      "region": "Southwest",
      "zoneRange": "6b-8a",
      "dominantZone": "7b",
      "lastFrost": "early April",
      "firstFrost": "late October",
      "coldestArea": "the Panhandle High Plains (zone 6b)",
      "warmestArea": "the south-central and southeast lowlands (zone 8a)"
    },
    {
      "state": "Oregon",
      "abbr": "OR",
      "region": "Pacific",
      "zoneRange": "4b-9b",
      "dominantZone": "8b",
      "lastFrost": "mid-April (Willamette Valley)",
      "firstFrost": "early November (Willamette Valley)",
      "coldestArea": "the high desert and Cascades east of the mountains (zone 4b)",
      "warmestArea": "the Willamette Valley and southwest interior (zone 9b)"
    },
    {
      "state": "Pennsylvania",
      "abbr": "PA",
      "region": "Northeast",
      "zoneRange": "5a-7b",
      "dominantZone": "6b",
      "lastFrost": "late April",
      "firstFrost": "mid-October",
      "coldestArea": "the northern Allegheny plateau (zone 5a)",
      "warmestArea": "the southeast around Philadelphia (zone 7b)"
    },
    {
      "state": "Rhode Island",
      "abbr": "RI",
      "region": "Northeast",
      "zoneRange": "6a-7b",
      "dominantZone": "7a",
      "lastFrost": "late April",
      "firstFrost": "mid-October",
      "coldestArea": "the northwest interior near Foster (zone 6a)",
      "warmestArea": "the Narragansett Bay shore and Newport (zone 7b)"
    },
    {
      "state": "South Carolina",
      "abbr": "SC",
      "region": "Southeast",
      "zoneRange": "7a-9a",
      "dominantZone": "8a",
      "lastFrost": "late March",
      "firstFrost": "early November",
      "coldestArea": "the Blue Ridge upstate near the mountains (zone 7a)",
      "warmestArea": "the Lowcountry coast around Charleston (zone 9a)"
    },
    {
      "state": "South Dakota",
      "abbr": "SD",
      "region": "Midwest",
      "zoneRange": "3b-5a",
      "dominantZone": "4b",
      "lastFrost": "mid-May",
      "firstFrost": "late September",
      "coldestArea": "the northern plains near North Dakota (zone 3b)",
      "warmestArea": "the southeast around Sioux Falls and the Black Hills foothills (zone 5a)"
    },
    {
      "state": "Tennessee",
      "abbr": "TN",
      "region": "Southeast",
      "zoneRange": "6a-8a",
      "dominantZone": "7a",
      "lastFrost": "mid-April",
      "firstFrost": "late October",
      "coldestArea": "the eastern Appalachian highlands (zone 6a)",
      "warmestArea": "the western Mississippi lowlands near Memphis (zone 8a)"
    },
    {
      "state": "Texas",
      "abbr": "TX",
      "region": "Southwest",
      "zoneRange": "6a-10a",
      "dominantZone": "8b",
      "lastFrost": "mid-March (most of state)",
      "firstFrost": "mid-November (most of state)",
      "coldestArea": "the northern Panhandle near Dalhart (zone 6a)",
      "warmestArea": "the lower Rio Grande Valley near Brownsville (zone 10a)"
    },
    {
      "state": "Utah",
      "abbr": "UT",
      "region": "West",
      "zoneRange": "4a-9a",
      "dominantZone": "6b",
      "lastFrost": "late April (Wasatch Front)",
      "firstFrost": "mid-October (Wasatch Front)",
      "coldestArea": "the high Uinta and central mountains (zone 4a)",
      "warmestArea": "the southwest Dixie around St. George (zone 9a)"
    },
    {
      "state": "Vermont",
      "abbr": "VT",
      "region": "Northeast",
      "zoneRange": "3b-5b",
      "dominantZone": "4b",
      "lastFrost": "mid-May",
      "firstFrost": "late September",
      "coldestArea": "the Green Mountains and Northeast Kingdom (zone 3b)",
      "warmestArea": "the Champlain Valley and southern river valleys (zone 5b)"
    },
    {
      "state": "Virginia",
      "abbr": "VA",
      "region": "Southeast",
      "zoneRange": "5b-8a",
      "dominantZone": "7b",
      "lastFrost": "mid-April",
      "firstFrost": "late October",
      "coldestArea": "the western Appalachian highlands (zone 5b)",
      "warmestArea": "the Tidewater and Hampton Roads coast (zone 8a)"
    },
    {
      "state": "Washington",
      "abbr": "WA",
      "region": "Pacific",
      "zoneRange": "4a-9a",
      "dominantZone": "8a",
      "lastFrost": "mid-April (Puget Sound)",
      "firstFrost": "early November (Puget Sound)",
      "coldestArea": "the Cascades and northeast highlands (zone 4a)",
      "warmestArea": "the Puget Sound lowland around Seattle (zone 9a)"
    },
    {
      "state": "Washington, DC",
      "abbr": "DC",
      "region": "Northeast",
      "zoneRange": "7b-8a",
      "dominantZone": "8a",
      "lastFrost": "mid-April",
      "firstFrost": "late October",
      "coldestArea": "outer neighborhoods away from the urban core (zone 7b)",
      "warmestArea": "the dense urban core, lifted by the city heat-island (zone 8a)"
    },
    {
      "state": "West Virginia",
      "abbr": "WV",
      "region": "Southeast",
      "zoneRange": "5b-7a",
      "dominantZone": "6b",
      "lastFrost": "late April",
      "firstFrost": "mid-October",
      "coldestArea": "the high Allegheny mountains near Davis (zone 5b)",
      "warmestArea": "the Ohio River valley near Huntington (zone 7a)"
    },
    {
      "state": "Wisconsin",
      "abbr": "WI",
      "region": "Midwest",
      "zoneRange": "3b-6a",
      "dominantZone": "5a",
      "lastFrost": "mid-May",
      "firstFrost": "early October",
      "coldestArea": "the north-central highlands near the UP line (zone 3b)",
      "warmestArea": "the Lake Michigan shore around Milwaukee (zone 6a)"
    },
    {
      "state": "Wyoming",
      "abbr": "WY",
      "region": "West",
      "zoneRange": "3a-6a",
      "dominantZone": "4b",
      "lastFrost": "late May",
      "firstFrost": "mid-September",
      "coldestArea": "the high mountain basins like Jackson Hole (zone 3a)",
      "warmestArea": "the lower southeast plains near Cheyenne (zone 6a)"
    }
  ]
}