Idaho frost dates: H
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Hagerman | May 3 | Oct 1 | 151 d | 7a |
| Hailey | May 13 | Oct 2 | 142 d | 6a |
| Hamer | Jun 3 | Sep 11 | 100 d | 5a |
| Hammett | May 1 | Oct 3 | 155 d | 7a |
| Hansen | May 6 | Oct 3 | 150 d | 6b |
| Harrison | Apr 22 | Oct 18 | 179 d | 6b |
| Harvard | May 15 | Sep 21 | 129 d | 6b |
| Hayden | Apr 22 | Oct 18 | 179 d | 6b |
| Hazelton | May 7 | Oct 5 | 151 d | 6b |
| Heyburn | May 7 | Oct 4 | 150 d | 6b |
| Hill City | Jun 16 | Sep 6 | 82 d | 5a |
| Holbrook | May 22 | Sep 20 | 121 d | 6a |
| Homedale | Apr 24 | Oct 9 | 168 d | 7a |
| Hope | May 8 | Sep 28 | 143 d | 6b |
| Horseshoe Bend | May 17 | Oct 12 | 148 d | 7a |
| Howe | May 24 | Sep 14 | 113 d | 5a |
| Huston | Apr 23 | Oct 18 | 178 d | 7a |