| 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 3b: -35°F to -30°F Zone 3a: -40°F to -35°F Zone 4b: -25°F to -20°F Zone 5a: -20°F to -15°F Zone 4a: -30°F to -25°F |
| 1990 Hardiness Zone: | Zone 4b: -25F to -20F |
| Average First Frost Date: | Sep.11 - Sep. 20 |
| Average Last Frost Date: | Jun. 11 - Jun. 20 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 43o - Unglaciated Montana High Plains |
| Heat Zone Days: | 15 - 30 days Over 86°F |
Annual Climate Data for ZIP Code 59011 - Big Timber, MT | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 13 | 17 | 23 | 30 | 39 | 47 | 52 | 51 | 41 | 32 | 23 | 16 | 32 |
| Avg Max Temp (°F) | 35 | 41 | 48 | 56 | 66 | 76 | 84 | 84 | 72 | 60 | 44 | 36 | 59 |
| Avg Precip (In.) | .63 | .48 | .91 | 1.76 | 2.78 | 2.56 | 1.54 | 1.25 | 1.29 | 1.37 | .71 | .67 | 15.95 |