Maine frost dates: B
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Bailey Island | May 2 | Oct 10 | 161 d | 6a |
| Baileyville | Apr 21 | Oct 26 | 188 d | 5b |
| Bangor | May 4 | Oct 4 | 153 d | 5a |
| Bar Harbor | Apr 27 | Oct 22 | 178 d | 6a |
| Bar Mills | May 7 | Oct 4 | 150 d | 5b |
| Bass Harbor | Apr 27 | Oct 22 | 178 d | 6a |
| Bath | May 10 | Oct 6 | 149 d | 6a |
| Beals | May 3 | Oct 9 | 159 d | 6a |
| Belfast | May 7 | Oct 5 | 151 d | 5b |
| Belgrade | Apr 27 | Oct 16 | 172 d | 5b |
| Belgrade Lakes | May 7 | Oct 2 | 148 d | 5a |
| Benedicta | May 13 | Sep 30 | 140 d | 5a |
| Bernard | Apr 27 | Oct 22 | 178 d | 6a |
| Berwick | Apr 30 | Oct 9 | 162 d | 6a |
| Bethel | May 6 | Oct 2 | 149 d | 5a |
| Biddeford | May 9 | Oct 3 | 147 d | 5b |
| Biddeford Pool | May 9 | Oct 3 | 147 d | 6a |
| Bingham | May 13 | Sep 30 | 140 d | 5a |
| Birch Harbor | Apr 27 | Oct 22 | 178 d | 6a |
| Blaine | May 25 | Sep 18 | 116 d | 4a |
| Blue Hill | May 8 | Oct 9 | 154 d | 5b |
| Boothbay | Apr 28 | Oct 21 | 176 d | 6a |
| Boothbay Harbor | Apr 28 | Oct 21 | 176 d | 6a |
| Bowdoin | May 15 | Oct 2 | 140 d | 5b |
| Bowdoinham | May 10 | Oct 6 | 149 d | 5b |
| Bradford | May 15 | Sep 28 | 136 d | 5a |
| Bradley | May 1 | Oct 6 | 158 d | 5a |
| Bremen | Apr 27 | Oct 18 | 174 d | 6a |
| Brewer | May 4 | Oct 4 | 153 d | 5a |
| Bridgewater | May 25 | Sep 18 | 116 d | 4b |
| Bridgton | May 5 | Oct 5 | 153 d | 5a |
| Bristol | Apr 27 | Oct 18 | 174 d | 6a |
| Brooklin | Apr 27 | Oct 22 | 178 d | 6a |
| Brooks | May 7 | Oct 5 | 151 d | 5a |
| Brooksville | May 7 | Oct 5 | 151 d | 5b |
| Brookton | May 6 | Oct 8 | 155 d | 5a |
| Brownfield | May 17 | Sep 25 | 131 d | 5a |
| Brownville | May 12 | Oct 1 | 142 d | 5a |
| Brownville Junction | May 12 | Oct 1 | 142 d | 5a |
| Brunswick | May 2 | Oct 10 | 161 d | 5b |
| Bryant Pond | May 12 | Sep 29 | 140 d | 5a |
| Buckfield | May 1 | Oct 10 | 162 d | 5b |
| Bucksport | May 4 | Oct 4 | 153 d | 5a |
| Burlington | May 4 | Oct 6 | 155 d | 5a |
| Burnham | May 2 | Oct 10 | 161 d | 5a |
| Bustins Island | May 2 | Oct 10 | 161 d | 6a |
| Buxton | May 7 | Oct 4 | 150 d | 5b |