| 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: | Sep. 21 - Sep. 30 | |
| Average Last Frost Date: | May 11 - May 20 | |
| Koppen-Geiger Climate Zone: | BSk - Cold Semi-Arid Climate | |
| Ecoregion: | 43g - Semiarid Pierre Shale Plains | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 46 - 60 days Over 86°F |
Annual Climate Data for ZIP Code 57717 - Belle Fourche, SD | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 10 | 15 | 22 | 32 | 43 | 52 | 57 | 55 | 44 | 33 | 21 | 12 | 33 |
| Avg Max Temp (°F) | 35 | 41 | 49 | 60 | 70 | 80 | 88 | 87 | 77 | 64 | 46 | 37 | 61 |
| Avg Precip (In.) | .46 | .53 | 1.05 | 1.96 | 3.02 | 3.09 | 2.04 | 1.41 | 1.29 | 1.74 | .7 | .6 | 17.88 |