USDA Plant Hardiness Zones
USDA hardiness zones group regions by their average annual minimum temperature in 5°F increments. Each numbered zone is split into "a" (colder half) and "b" (warmer half). Zones are the most reliable starting point for deciding what perennials and woody plants will survive winter in your area.
All zones
| Zone | Min temperature | Growing season | Sample regions |
|---|---|---|---|
| 3a | -40°F to -35°F | 90 days | Interior Alaska; Northern Minnesota |
| 3b | -35°F to -30°F | 100 days | Northern Maine; Upper Michigan |
| 4a | -30°F to -25°F | 120 days | Northern Vermont; Northern Wisconsin |
| 4b | -25°F to -20°F | 130 days | Central Vermont; Northern Iowa |
| 5a | -20°F to -15°F | 150 days | Maine; Western New York |
| 5b | -15°F to -10°F | 165 days | Southern Vermont; Central Ohio |
| 6a | -10°F to -5°F | 180 days | Northern New Jersey; Central Missouri |
| 6b | -5°F to 0°F | 190 days | Long Island; Southern Indiana |
| 7a | 0°F to 5°F | 210 days | Northern Virginia; Northern North Carolina |
| 7b | 5°F to 10°F | 220 days | Central North Carolina (Chapel Hill, Raleigh); Northern Georgia |
| 8a | 10°F to 15°F | 240 days | Southern Georgia; Central Texas |
| 8b | 15°F to 20°F | 260 days | Northern Florida; Coastal Texas |
| 9a | 20°F to 25°F | 290 days | Central Florida; Coastal California |
| 9b | 25°F to 30°F | 310 days | Southern Florida (north); Houston, TX |
| 10a | 30°F to 35°F | 340 days | South Florida; Coastal Southern California |
| 10b | 35°F to 40°F | 365 days | Miami, FL; Florida Keys |
| 11a | 40°F to 45°F | 365 days | Lower Florida Keys; Hawaii (lower elevations) |