New Hampshire frost dates: M
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Madbury | May 3 | Oct 10 | 160 d | 6a |
| Madison | May 16 | Sep 26 | 133 d | 5a |
| Manchester | Apr 30 | Oct 11 | 164 d | 6a |
| Marlborough | May 14 | Oct 1 | 140 d | 6a |
| Marlow | May 8 | Oct 3 | 148 d | 6a |
| Melvin Village | May 6 | Oct 6 | 153 d | 5b |
| Meredith | Apr 28 | Oct 16 | 171 d | 5b |
| Meriden | May 8 | Oct 6 | 151 d | 5a |
| Merrimack | Apr 30 | Oct 12 | 165 d | 6a |
| Milan | May 30 | Sep 19 | 112 d | 4b |
| Milford | May 3 | Oct 5 | 155 d | 6a |
| Milton | Apr 30 | Oct 9 | 162 d | 5b |
| Milton Mills | May 16 | Sep 30 | 137 d | 5b |
| Mirror Lake | Apr 28 | Oct 16 | 171 d | 5b |
| Monroe | May 13 | Oct 3 | 143 d | 4b |
| Mont Vernon | May 3 | Oct 5 | 155 d | 6a |
| Moultonborough | Apr 28 | Oct 16 | 171 d | 5b |
| Mount Washington | May 19 | Sep 29 | 133 d | 4a |