Maine planting zones & frost dates
USDA hardiness zones in Maine go from 5a to 6a. Pick your city for its average frost dates and a planting calendar, or search by ZIP code.
| City | Zone | Avg. last frost | Avg. first frost |
|---|---|---|---|
| Auburn | 5b | Apr 25 | Oct 19 |
| Augusta | 5b | Apr 27 | Oct 16 |
| Bangor | 5a | May 4 | Oct 4 |
| Biddeford | 5b | May 9 | Oct 3 |
| Brunswick | 5b | May 2 | Oct 10 |
| Lewiston | 5b | Apr 25 | Oct 19 |
| Portland | 6a | Apr 26 | Oct 15 |
| Saco | 5b | May 9 | Oct 3 |
| Sanford | 5b | May 16 | Sep 30 |
| South Portland | 6a | Apr 26 | Oct 15 |
| South Portland Gardens | 6a | Apr 26 | Oct 15 |
| Waterville | 5b | May 2 | Oct 10 |
| Wells Beach Station | 6a | May 9 | Oct 3 |
| West Scarborough | 6a | Apr 26 | Oct 15 |
| Westbrook | 5b | Apr 26 | Oct 15 |
| York Beach | 6a | May 1 | Oct 14 |
Cities with 10,000+ residents. Data: USDA Plant Hardiness Zone Map 2023 and NOAA Climate Normals 1991–2020. Sources and method.