Williston, North Dakota has a Cold Semi-Arid Climate climate (Köppen classification: BSk). Average annual temperatures range from -0.8 °C (low) to 12.5 °C (high). Annual precipitation averages 380 Millimeters. Williston is located in USDA Plant Hardiness Zone 4a. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -16.2 °C | -5.2 °C | 10.41 mm |
| February | -13.8 °C | -2.4 °C | 6.86 mm |
| March | -7.8 °C | 4.5 °C | 12.7 mm |
| April | -0.9 °C | 13.3 °C | 25.91 mm |
| May | 5.3 °C | 19.5 °C | 57.91 mm |
| June | 10.9 °C | 24.6 °C | 72.9 mm |
| July | 13.9 °C | 29 °C | 69.09 mm |
| August | 12.4 °C | 28.9 °C | 39.88 mm |
| September | 6.7 °C | 22.9 °C | 35.05 mm |
| October | 0.1 °C | 13.9 °C | 24.38 mm |
| November | -7.4 °C | 4.2 °C | 13.72 mm |
| December | -13.3 °C | -2.8 °C | 11.18 mm |
| Annual | -0.8 °C | 12.5 °C | 379.99 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 150-180 Days |
| Plant Hardiness Zone | Zone 4a : -34.4°C to -31.7°C |
| Plant Hardiness Zone - 2012 | Zone 4a : -34.4°C to -31.7°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | BSk - Cold Semi-Arid Climate |