| 2023 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 | |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 4b: -25°F to -20°F Zone 4a: -30°F to -25°F | |
| 1990 Hardiness Zone: | Zone 4b: -25F to -20F | |
| Average First Frost Date: | Aug. 21 - Aug. 31 | |
| Average Last Frost Date: | Jun. 21 - Jun. 30 | |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year | |
| Ecoregion: | 17w - Townsend Basin | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 59632 - Boulder, MT | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 10 | 14 | 20 | 27 | 35 | 42 | 47 | 46 | 37 | 28 | 18 | 11 | 28 |
| Avg Max Temp (°F) | 33 | 38 | 45 | 54 | 63 | 72 | 80 | 81 | 70 | 58 | 41 | 34 | 56 |
| Avg Precip (In.) | .41 | .31 | .53 | .77 | 1.98 | 2 | 1.53 | 1.45 | 1.06 | .61 | .56 | .43 | 11.65 |