Williston, Tennessee has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 9.9 °C (low) to 22.1 °C (high). Annual precipitation averages 1415.5 Millimeters. Williston is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Oct. 21 - Oct. 31.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -1.2 °C | 9.8 °C | 109.98 mm |
| February | 0.5 °C | 12.4 °C | 120.14 mm |
| March | 4.6 °C | 17.2 °C | 140.46 mm |
| April | 9.3 °C | 22.5 °C | 146.3 mm |
| May | 14.8 °C | 26.6 °C | 133.86 mm |
| June | 19.2 °C | 30.7 °C | 114.05 mm |
| July | 21.1 °C | 32.2 °C | 113.54 mm |
| August | 20.1 °C | 32.2 °C | 83.31 mm |
| September | 16.1 °C | 29.3 °C | 99.31 mm |
| October | 9.4 °C | 23.6 °C | 106.43 mm |
| November | 3.8 °C | 16.8 °C | 108.2 mm |
| December | 0.5 °C | 11.3 °C | 139.95 mm |
| Annual | 9.9 °C | 22.1 °C | 1415.53 mm |
| Average First Frost Date | Oct. 21 - Oct. 31 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 50-75 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7b : -15°C to -12.2°C |
| Current Drought Conditions | Normal |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |