Idaho frost dates: M
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Mackay | Jun 1 | Sep 20 | 111 d | 5a |
| Macks Inn | frost any month | 4a | ||
| Malad City | May 22 | Sep 20 | 121 d | 6a |
| Malta | Jun 5 | Sep 13 | 100 d | 6a |
| Marsing | Apr 23 | Oct 18 | 178 d | 7a |
| May | Jun 12 | Sep 6 | 86 d | 5a |
| McCall | Jun 10 | Sep 10 | 92 d | 5a |
| McCammon | May 23 | Sep 24 | 124 d | 5b |
| Medimont | May 3 | Oct 4 | 154 d | 6b |
| Melba | Apr 12 | Oct 26 | 197 d | 7a |
| Menan | May 9 | Oct 5 | 149 d | 5a |
| Meridian | Apr 29 | Oct 13 | 167 d | 7a |
| Mesa | May 10 | Oct 2 | 145 d | 6a |
| Middleton | Apr 29 | Oct 13 | 167 d | 7a |
| Midvale | May 15 | Sep 27 | 135 d | 6a |
| Minidoka | May 16 | Oct 1 | 138 d | 6a |
| Monteview | Jun 12 | Sep 7 | 87 d | 4b |
| Montpelier | Jun 17 | Sep 3 | 78 d | 5a |
| Moore | May 22 | Sep 22 | 123 d | 5a |
| Moreland | May 5 | Oct 3 | 151 d | 5b |
| Moscow | frost any month | 6b | ||
| Mountain Home | May 2 | Oct 8 | 159 d | 6b |
| Mountain Home Afb | Apr 30 | Oct 17 | 170 d | 7a |
| Moyie Springs | Apr 30 | Oct 4 | 157 d | 6b |
| Mullan | May 12 | Sep 30 | 141 d | 6a |
| Murphy | May 31 | Oct 6 | 128 d | 7a |
| Murray | May 31 | Sep 5 | 97 d | 6a |
| Murtaugh | May 7 | Oct 5 | 151 d | 6b |