Williamson, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11 °C (low) to 22.8 °C (high). Annual precipitation averages 1303 Millimeters. Williamson is located in USDA Plant Hardiness Zone 8a. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 1.1 °C | 12.6 °C | 118.62 mm |
| February | 2.6 °C | 14.7 °C | 121.16 mm |
| March | 6 °C | 18.9 °C | 129.29 mm |
| April | 10.1 °C | 22.9 °C | 106.17 mm |
| May | 15.2 °C | 27 °C | 84.33 mm |
| June | 19.1 °C | 30.2 °C | 109.47 mm |
| July | 20.9 °C | 31.7 °C | 129.29 mm |
| August | 20.6 °C | 31.2 °C | 107.44 mm |
| September | 17.3 °C | 28.4 °C | 92.2 mm |
| October | 11.3 °C | 23.4 °C | 81.53 mm |
| November | 5.4 °C | 18.2 °C | 99.06 mm |
| December | 2.4 °C | 13.8 °C | 124.46 mm |
| Annual | 11 °C | 22.8 °C | 1303.02 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8a : -12.2°C to -9.4°C |
| Plant Hardiness Zone - 2012 | Zone 8a : -12.2°C to -9.4°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |