| 2023 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 5a: -20°F to -15°F Zone 4b: -25°F to -20°F |
| 1990 Hardiness Zone: | Zone 5a: -20F to -15F |
| Average First Frost Date: | Oct. 1 - Oct. 10 |
| Average Last Frost Date: | May 11 - May 20 |
| Koppen-Geiger Climate Zone: | Dfb - Humid Continental Mild Summer, Wet All Year |
| Ecoregion: | 43n - Central Grassland |
| Heat Zone Days: | 31 - 45 days Over 86°F |
Annual Climate Data for ZIP Code 59102 - Billings, MT | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 14 | 19 | 25 | 34 | 43 | 51 | 57 | 55 | 45 | 35 | 24 | 16 | 35 |
| Avg Max Temp (°F) | 34 | 41 | 49 | 59 | 69 | 79 | 87 | 86 | 74 | 61 | 44 | 36 | 60 |
| Avg Precip (In.) | .75 | .56 | 1.06 | 1.7 | 2.5 | 1.93 | 1.29 | .88 | 1.36 | 1.26 | .71 | .63 | 14.64 |