| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 4b: -25°F to -20°F Zone 5b: -15°F to -10°F | |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F Zone 4b: -25°F to -20°F Zone 4a: -30°F to -25°F | |
| 1990 Hardiness Zone: | Zone 4a: -30F to -25F | |
| Average First Frost Date: | Sep.1 - Sep. 10 | |
| Average Last Frost Date: | Jun. 11 - Jun. 20 | |
| Koppen-Geiger Climate Zone: | BSk - Cold Semi-Arid Climate | |
| Ecoregion: | 17aa - Dry Intermontane Sagebrush Valleys | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 59729 - Ennis, MT | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 14 | 17 | 23 | 29 | 36 | 43 | 47 | 46 | 38 | 31 | 22 | 15 | 30 |
| Avg Max Temp (°F) | 33 | 39 | 46 | 55 | 64 | 74 | 82 | 81 | 71 | 59 | 42 | 34 | 57 |
| Avg Precip (In.) | .49 | .45 | .92 | 1.29 | 2.29 | 2.36 | 1.43 | 1.39 | 1.18 | .98 | .6 | .46 | 13.84 |