Jefferson, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 10.4 °C (low) to 22.4 °C (high). Annual precipitation averages 1323.9 Millimeters. Jefferson is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 11 - Mar. 20 through the first frost around Nov. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.3 °C | 11.8 °C | 119.89 mm |
| February | 1.8 °C | 13.8 °C | 118.11 mm |
| March | 5.2 °C | 18.2 °C | 120.14 mm |
| April | 9.4 °C | 22.7 °C | 102.36 mm |
| May | 14.3 °C | 26.6 °C | 92.2 mm |
| June | 18.8 °C | 30.3 °C | 124.46 mm |
| July | 20.7 °C | 32.1 °C | 111 mm |
| August | 20.2 °C | 31.3 °C | 119.63 mm |
| September | 16.9 °C | 28.4 °C | 101.85 mm |
| October | 10.6 °C | 23.2 °C | 92.46 mm |
| November | 4.6 °C | 17.7 °C | 101.35 mm |
| December | 1.7 °C | 13.1 °C | 120.4 mm |
| Annual | 10.4 °C | 22.4 °C | 1323.85 mm |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 50-75 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 | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |