Wilsall, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -1.8 °C (low) to 13.5 °C (high). Annual precipitation averages 384.6 Millimeters. Wilsall is located in USDA Plant Hardiness Zone 4b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep.11 - Sep. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.6 °C | 1.6 °C | 13.97 mm |
| February | -9.7 °C | 2.5 °C | 11.43 mm |
| March | -6.1 °C | 7.2 °C | 22.35 mm |
| April | -2.7 °C | 12.3 °C | 36.83 mm |
| May | 1.6 °C | 17 °C | 62.48 mm |
| June | 5.6 °C | 22.2 °C | 68.07 mm |
| July | 8.4 °C | 28.2 °C | 35.31 mm |
| August | 7.3 °C | 28.2 °C | 28.19 mm |
| September | 3.4 °C | 22.1 °C | 36.32 mm |
| October | -1.7 °C | 14.2 °C | 31.5 mm |
| November | -6.7 °C | 5.9 °C | 19.81 mm |
| December | -10.4 °C | 1 °C | 18.29 mm |
| Annual | -1.8 °C | 13.5 °C | 384.55 mm |
| Average First Frost Date | Sep.11 - Sep. 20 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | Over 180 Days |
| Plant Hardiness Zone | Zone 4b : -31.7°C to -28.9°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |