Willow Creek, Montana has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -0.6 °C (low) to 14.4 °C (high). Annual precipitation averages 286.5 Millimeters. Willow Creek is located in USDA Plant Hardiness Zone 5a. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -10.2 °C | 1.5 °C | 8.89 mm |
| February | -8.7 °C | 3.7 °C | 8.64 mm |
| March | -5.1 °C | 8.8 °C | 17.02 mm |
| April | -1.2 °C | 13.2 °C | 34.8 mm |
| May | 3.5 °C | 18.3 °C | 46.99 mm |
| June | 7.3 °C | 23.1 °C | 54.61 mm |
| July | 10.2 °C | 29.6 °C | 25.15 mm |
| August | 8.9 °C | 29.2 °C | 21.84 mm |
| September | 4.8 °C | 23.1 °C | 23.88 mm |
| October | -0.7 °C | 14.8 °C | 18.8 mm |
| November | -6.1 °C | 6.7 °C | 13.72 mm |
| December | -10.1 °C | 1.3 °C | 12.19 mm |
| Annual | -0.6 °C | 14.4 °C | 286.53 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 5a : -28.9°C to -26.1°C |
| Plant Hardiness Zone - 2012 | Zone 4b : -31.7°C to -28.9°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |