Thomaston, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11.1 °C (low) to 23.7 °C (high). Annual precipitation averages 1296.7 Millimeters. Thomaston is located in USDA Plant Hardiness Zone 8b. 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 | 1.3 °C | 13.6 °C | 116.33 mm |
| February | 2.8 °C | 15.7 °C | 115.57 mm |
| March | 6.2 °C | 19.9 °C | 135.38 mm |
| April | 10.1 °C | 24 °C | 99.57 mm |
| May | 15.1 °C | 28 °C | 83.82 mm |
| June | 19.2 °C | 30.9 °C | 102.87 mm |
| July | 21 °C | 32.4 °C | 136.14 mm |
| August | 20.7 °C | 31.9 °C | 114.55 mm |
| September | 17.5 °C | 29.4 °C | 93.22 mm |
| October | 11.4 °C | 24.5 °C | 78.23 mm |
| November | 5.7 °C | 19.1 °C | 97.03 mm |
| December | 2.7 °C | 14.7 °C | 123.95 mm |
| Annual | 11.1 °C | 23.7 °C | 1296.66 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 8b : -9.4°C to -6.7°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 |