Montana frost dates: T
| City | Last frost | First frost | Season | Zone |
|---|---|---|---|---|
| Teigen | May 20 | Sep 24 | 127 d | 4b |
| Terry | May 12 | Sep 28 | 139 d | 4a |
| Thompson Falls | May 7 | Oct 4 | 150 d | 6a |
| Three Forks | May 9 | Sep 27 | 141 d | 5a |
| Toston | May 19 | Sep 19 | 123 d | 5a |
| Townsend | May 19 | Sep 19 | 123 d | 4b |
| Trego | May 16 | Sep 18 | 125 d | 5a |
| Trout Creek | May 20 | Sep 21 | 124 d | 6a |
| Troy | May 14 | Sep 25 | 134 d | 6a |
| Turner | May 19 | Sep 21 | 125 d | 4a |
| Twin Bridges | Jun 8 | Sep 2 | 86 d | 5a |
| Two Dot | May 23 | Sep 16 | 116 d | 4b |