Frost dates in Maine
Across Maine, the typical last spring frost is around May 6 and the first fall frost around Oct 6. Your own dates depend on where you are in the state; find your county below.
Most of the state's last spring frosts fall between Apr 27 and May 16, and its first fall frosts between Sep 26 and Oct 21.
These are the dates with a 50% chance of a 32°F frost on or after (spring) or on or before (fall), so plan tender crops a week or two after the spring date and keep row cover handy. For dates at your exact ZIP code, use the zone and frost date lookup; for what to plant when, see the planting guide by frost date.
Hardiness zones in Maine: zone 3b, zone 4a, zone 4b, zone 5a, zone 5b, zone 6a, zone 6b, zone 7a
Frost dates by county in Maine
| County | Last spring frost | First fall frost | Growing season |
|---|---|---|---|
| Androscoggin | May 3 | Oct 10 | About 160 days |
| Aroostook | May 16 | Sep 26 | About 133 days |
| Cumberland | Apr 30 | Oct 15 | About 168 days |
| Franklin | May 16 | Sep 26 | About 133 days |
| Hancock | May 1 | Oct 22 | About 174 days |
| Kennebec | May 2 | Oct 10 | About 161 days |
| Knox | Apr 27 | Oct 19 | About 175 days |
| Lincoln | Apr 28 | Oct 18 | About 173 days |
| Oxford | May 6 | Oct 2 | About 149 days |
| Penobscot | May 6 | Oct 4 | About 151 days |
| Piscataquis | May 12 | Oct 1 | About 142 days |
| Sagadahoc | May 8 | Oct 10 | About 155 days |
| Somerset | May 8 | Oct 2 | About 147 days |
| Waldo | May 7 | Oct 5 | About 151 days |
| Washington | May 3 | Oct 9 | About 159 days |
| York | May 9 | Oct 3 | About 147 days |
Source: NOAA NCEI U.S. Climate Normals 1991–2020, 50% probability of 32°F, from the weather station nearest each ZIP code; each county shows the middle value across its ZIP codes. Hills, valleys and cities can run a week or more earlier or later.