USDA Hardiness Zones: Frost Dates & Planting Calendars
Typical frost dates and a planting calendar for each USDA hardiness zone, based on 4,807 US cities. Zones measure winter cold, so local frost dates within a zone can differ by weeks.
| Zone | Winter low | Typical last frost | Typical first frost | Cities |
|---|---|---|---|---|
| Zone 2a | −50°F to −45°F | May 22 | Sep 2 | 1 |
| Zone 2b | −45°F to −40°F | May 18 | Sep 6 | 1 |
| Zone 3a | −40°F to −35°F | May 16 | Sep 6 | 1 |
| Zone 3b | −35°F to −30°F | May 17 | Sep 23 | 4 |
| Zone 4a | −30°F to −25°F | May 10 | Sep 29 | 26 |
| Zone 4b | −25°F to −20°F | May 5 | Oct 4 | 79 |
| Zone 5a | −20°F to −15°F | Apr 30 | Oct 8 | 166 |
| Zone 5b | −15°F to −10°F | Apr 29 | Oct 14 | 248 |
| Zone 6a | −10°F to −5°F | Apr 26 | Oct 20 | 486 |
| Zone 6b | −5°F to 0°F | Apr 22 | Oct 23 | 615 |
| Zone 7a | 0°F to 5°F | Apr 15 | Oct 27 | 549 |
| Zone 7b | 5°F to 10°F | Apr 5 | Nov 4 | 635 |
| Zone 8a | 10°F to 15°F | Mar 28 | Nov 8 | 338 |
| Zone 8b | 15°F to 20°F | Mar 16 | Nov 15 | 392 |
| Zone 9a | 20°F to 25°F | Mar 1 | Nov 27 | 248 |
| Zone 9b | 25°F to 30°F | Jan 31 | Dec 10 | 379 |
| Zone 10a | 30°F to 35°F | Jan 17 | Jan 13 | 320 |
| Zone 10b | 35°F to 40°F | Jan 13 | Jan 13 | 175 |
| Zone 11a | 40°F to 45°F | Jan 18 | Jan 13 | 82 |
| Zone 11b | 45°F to 50°F | Frost-free | Frost-free | 1 |
| Zone 12a | 50°F to 55°F | Frost-free | Frost-free | 19 |
| Zone 12b | 55°F to 60°F | Frost-free | Frost-free | 40 |
| Zone 13a | 60°F to 65°F | Frost-free | Frost-free | 1 |