Smyrna, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 50.7 °F (low) to 71.1 °F (high). Annual precipitation averages 53.8 Inches. Smyrna 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. 11 - Nov. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 32.0 °F | 52.0 °F | 4.81 in. |
| February | 34.6 °F | 56.0 °F | 4.74 in. |
| March | 41.3 °F | 64.0 °F | 4.93 in. |
| April | 49.2 °F | 71.8 °F | 4.3 in. |
| May | 58.3 °F | 78.7 °F | 4.2 in. |
| June | 66.2 °F | 84.7 °F | 4.42 in. |
| July | 69.5 °F | 87.5 °F | 5.28 in. |
| August | 68.8 °F | 86.9 °F | 4.09 in. |
| September | 62.7 °F | 81.9 °F | 4.21 in. |
| October | 51.1 °F | 72.5 °F | 3.72 in. |
| November | 40.0 °F | 62.6 °F | 4.18 in. |
| December | 35.0 °F | 54.4 °F | 4.89 in. |
| Annual | 50.7 °F | 71.1 °F | 53.77 in. |
| Average First Frost Date | Nov. 11 - Nov. 20 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| 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 | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |