Decatur, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 51 °F (low) to 71.6 °F (high). Annual precipitation averages 53.9 Inches. Decatur is located in USDA Plant Hardiness Zone 8a. 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 | 32.0 °F | 52.2 °F | 4.71 in. |
| February | 34.9 °F | 56.1 °F | 4.84 in. |
| March | 41.5 °F | 64.2 °F | 5.13 in. |
| April | 49.5 °F | 72.2 °F | 4.22 in. |
| May | 58.7 °F | 79.5 °F | 3.84 in. |
| June | 66.6 °F | 85.7 °F | 4.44 in. |
| July | 69.9 °F | 88.4 °F | 5.16 in. |
| August | 69.1 °F | 87.8 °F | 4.37 in. |
| September | 63.1 °F | 82.5 °F | 4.16 in. |
| October | 51.6 °F | 73.1 °F | 3.82 in. |
| November | 40.5 °F | 62.8 °F | 4.36 in. |
| December | 35.1 °F | 54.7 °F | 4.83 in. |
| Annual | 51 °F | 71.6 °F | 53.88 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 11 - Mar. 20 |
| Average Days With Frost | 40-50 Days |
| Plant Hardiness Zone | Zone 8a : 10°F to 15°F |
| Plant Hardiness Zone - 2012 | Zone 7b : 5°F to 10°F |
| Current Drought Conditions | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |