{
  "name": "USDA Plant Hardiness Zones — full reference table (1–13)",
  "description": "Open reference table of all 13 USDA Plant Hardiness Zones: average annual minimum temperature in °F and °C, average last spring and first fall frost, growing-season length, representative US regions, and signature plantings. Free CSV + JSON, CC-BY 4.0.",
  "url": "https://www.getgrowli.app/data/usda-hardiness-zones",
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "creditText": "USDA hardiness-zone 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": "Temperature bands are the published USDA Plant Hardiness Zone Map (2023 revision) 10 °F zone definitions. Frost-date and growing-season figures are mid-zone US national averages derived from NOAA Climate Data Online normals; local dates vary by ZIP code. Region and signature-planting columns are editorial summaries for orientation, not climate measurements.",
  "spatialCoverage": "US",
  "lastVerified": "2026-05-15",
  "recordCount": 13,
  "data": [
    {
      "zone": 1,
      "tempRangeF": "-60 to -50°F",
      "tempRangeC": "-51 to -46°C",
      "lastFrost": "mid-June",
      "firstFrost": "mid-August",
      "growingDays": 60,
      "regions": "Interior Alaska (Fairbanks region)",
      "signature": "Sub-arctic. Only the hardiest cold-tolerant crops and trees survive."
    },
    {
      "zone": 2,
      "tempRangeF": "-50 to -40°F",
      "tempRangeC": "-46 to -40°C",
      "lastFrost": "early June",
      "firstFrost": "late August",
      "growingDays": 90,
      "regions": "Northern Alaska, parts of northern Canada",
      "signature": "Very short season. Cold-hardy vegetables and shrubs only."
    },
    {
      "zone": 3,
      "tempRangeF": "-40 to -30°F",
      "tempRangeC": "-40 to -34°C",
      "lastFrost": "late May",
      "firstFrost": "early September",
      "growingDays": 110,
      "regions": "Northern Minnesota, North Dakota, interior Alaska",
      "signature": "Cold-hardy fruit trees plus most cool-season vegetables."
    },
    {
      "zone": 4,
      "tempRangeF": "-30 to -20°F",
      "tempRangeC": "-34 to -29°C",
      "lastFrost": "mid-May",
      "firstFrost": "mid-September",
      "growingDays": 125,
      "regions": "Northern Maine, northern Wisconsin, Montana, parts of New England",
      "signature": "Cold-climate gardening. Most vegetables, many fruit trees, hardy ornamentals."
    },
    {
      "zone": 5,
      "tempRangeF": "-20 to -10°F",
      "tempRangeC": "-29 to -23°C",
      "lastFrost": "late April / early May",
      "firstFrost": "late September / early October",
      "growingDays": 150,
      "regions": "Iowa, southern Wisconsin, northern Illinois, parts of New York",
      "signature": "Productive Midwest gardening. Wide vegetable selection, robust fruit production."
    },
    {
      "zone": 6,
      "tempRangeF": "-10 to 0°F",
      "tempRangeC": "-23 to -18°C",
      "lastFrost": "mid- to late April",
      "firstFrost": "mid- to late October",
      "growingDays": 180,
      "regions": "Southern Pennsylvania, Ohio, Missouri, parts of mid-Atlantic",
      "signature": "Long-season productive zone. Almost every common vegetable and most fruits."
    },
    {
      "zone": 7,
      "tempRangeF": "0 to 10°F",
      "tempRangeC": "-18 to -12°C",
      "lastFrost": "mid-April",
      "firstFrost": "late October / early November",
      "growingDays": 200,
      "regions": "Virginia, North Carolina (mountains), Oklahoma, Tennessee",
      "signature": "Long warm season + mild winters. Wide crop selection including figs and pomegranates."
    },
    {
      "zone": 8,
      "tempRangeF": "10 to 20°F",
      "tempRangeC": "-12 to -7°C",
      "lastFrost": "mid- to late March",
      "firstFrost": "mid-November",
      "growingDays": 230,
      "regions": "Texas (much of), Louisiana, North Florida, Oregon coast, Washington (parts)",
      "signature": "Mild winters, hot summers. Subtropical possibilities mixed with temperate."
    },
    {
      "zone": 9,
      "tempRangeF": "20 to 30°F",
      "tempRangeC": "-7 to -1°C",
      "lastFrost": "mid-February to early March",
      "firstFrost": "late November / early December",
      "growingDays": 280,
      "regions": "Central + South Florida, Southern Texas, Southern California, Arizona",
      "signature": "Subtropical. Year-round growing for most crops. Frost is rare and brief."
    },
    {
      "zone": 10,
      "tempRangeF": "30 to 40°F",
      "tempRangeC": "-1 to 4°C",
      "lastFrost": "frost rare or never",
      "firstFrost": "frost rare or never",
      "growingDays": 365,
      "regions": "South Florida, Coastal Southern California, Hawaii (parts)",
      "signature": "Tropical. Year-round growing. True frost-free climate."
    },
    {
      "zone": 11,
      "tempRangeF": "40 to 50°F",
      "tempRangeC": "4 to 10°C",
      "lastFrost": "no frost",
      "firstFrost": "no frost",
      "growingDays": 365,
      "regions": "Florida Keys, Hawaii (most), Puerto Rico, southern California (coastal)",
      "signature": "Frost-free tropical. Year-round all crops except those needing cold dormancy."
    },
    {
      "zone": 12,
      "tempRangeF": "50 to 60°F",
      "tempRangeC": "10 to 16°C",
      "lastFrost": "no frost",
      "firstFrost": "no frost",
      "growingDays": 365,
      "regions": "Hawaii (lowland), Puerto Rico (parts)",
      "signature": "Tropical lowland. Heat-adapted plants only."
    },
    {
      "zone": 13,
      "tempRangeF": "60 to 70°F",
      "tempRangeC": "16 to 21°C",
      "lastFrost": "no frost",
      "firstFrost": "no frost",
      "growingDays": 365,
      "regions": "Hawaii (coastal lowlands), Puerto Rico (south coast)",
      "signature": "Hot tropical. Strictly tropical species."
    }
  ]
}