Sumner, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 13.2 °C (low) to 24.8 °C (high). Annual precipitation averages 1262.1 Millimeters. Sumner is located in USDA Plant Hardiness Zone 9a. The growing season typically runs from the last frost around Mar. 1 - Mar. 10 through the first frost around Nov. 21 - Nov. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 3.7 °C | 15.3 °C | 116.59 mm |
| February | 5.3 °C | 17.4 °C | 108.46 mm |
| March | 8.4 °C | 21.2 °C | 125.73 mm |
| April | 12.5 °C | 24.8 °C | 91.19 mm |
| May | 17.2 °C | 28.9 °C | 73.66 mm |
| June | 20.9 °C | 31.4 °C | 129.79 mm |
| July | 22.2 °C | 32.6 °C | 127.25 mm |
| August | 21.9 °C | 32.2 °C | 123.19 mm |
| September | 19.3 °C | 30.2 °C | 107.7 mm |
| October | 13.8 °C | 25.8 °C | 75.95 mm |
| November | 7.9 °C | 20.6 °C | 76.45 mm |
| December | 5.1 °C | 16.6 °C | 106.17 mm |
| Annual | 13.2 °C | 24.8 °C | 1262.13 mm |
| Average First Frost Date | Nov. 21 - Nov. 30 |
| Average Last Frost Date | Mar. 1 - Mar. 10 |
| Average Days With Frost | 20-30 Days |
| Plant Hardiness Zone | Zone 9a : -6.7°C to -3.9°C |
| Plant Hardiness Zone - 2012 | Zone 8b : -9.4°C to -6.7°C |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |