{
  "name": "GardeningByZone — Average Frost Dates by USDA Hardiness Zone",
  "description": "Representative average last-spring and first-fall frost dates for each USDA plant hardiness zone, used to compute the planting calendars on gardeningbyzone.com.",
  "source": "USDA Plant Hardiness Zone averages",
  "methodology": "https://gardeningbyzone.com/methodology/",
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "attribution": "Data: GardeningByZone (gardeningbyzone.com)",
  "last_updated": "2026-06-09",
  "zones": [{
      "zone": "2A",
      "region": "great-plains",
      "last_spring_frost": "May 30",
      "first_fall_frost": "Sep 1",
      "frost_free_days": 94
    },{
      "zone": "3B",
      "region": "great-plains",
      "last_spring_frost": "May 15",
      "first_fall_frost": "Sep 15",
      "frost_free_days": 123
    },{
      "zone": "4A",
      "region": "midwest",
      "last_spring_frost": "May 8",
      "first_fall_frost": "Sep 25",
      "frost_free_days": 140
    },{
      "zone": "4B",
      "region": "midwest",
      "last_spring_frost": "May 1",
      "first_fall_frost": "Oct 1",
      "frost_free_days": 153
    },{
      "zone": "5A",
      "region": "midwest",
      "last_spring_frost": "Apr 25",
      "first_fall_frost": "Oct 8",
      "frost_free_days": 166
    },{
      "zone": "5B",
      "region": "midwest",
      "last_spring_frost": "Apr 18",
      "first_fall_frost": "Oct 13",
      "frost_free_days": 178
    },{
      "zone": "6A",
      "region": "midwest",
      "last_spring_frost": "Apr 21",
      "first_fall_frost": "Oct 15",
      "frost_free_days": 177
    },{
      "zone": "6B",
      "region": "midwest",
      "last_spring_frost": "Apr 10",
      "first_fall_frost": "Oct 20",
      "frost_free_days": 193
    },{
      "zone": "7A",
      "region": "southeast",
      "last_spring_frost": "Apr 5",
      "first_fall_frost": "Oct 28",
      "frost_free_days": 206
    },{
      "zone": "7B",
      "region": "southeast",
      "last_spring_frost": "Mar 28",
      "first_fall_frost": "Nov 3",
      "frost_free_days": 220
    },{
      "zone": "8A",
      "region": "southeast",
      "last_spring_frost": "Mar 20",
      "first_fall_frost": "Nov 10",
      "frost_free_days": 235
    },{
      "zone": "8B",
      "region": "southeast",
      "last_spring_frost": "Mar 12",
      "first_fall_frost": "Nov 18",
      "frost_free_days": 251
    },{
      "zone": "9A",
      "region": "texas",
      "last_spring_frost": "Feb 28",
      "first_fall_frost": "Nov 28",
      "frost_free_days": 273
    },{
      "zone": "9B",
      "region": "florida",
      "last_spring_frost": "Feb 15",
      "first_fall_frost": "Dec 10",
      "frost_free_days": 298
    },{
      "zone": "10A",
      "region": "florida",
      "last_spring_frost": "Feb 1",
      "first_fall_frost": "Dec 20",
      "frost_free_days": 322
    },{
      "zone": "10B",
      "region": "florida",
      "last_spring_frost": "Jan 15",
      "first_fall_frost": "Dec 31",
      "frost_free_days": 350
    },{
      "zone": "11A",
      "region": "florida",
      "last_spring_frost": "Jan 1",
      "first_fall_frost": "Dec 31",
      "frost_free_days": 364
    }
  ]
}