Marietta, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 50.5 °F (low) to 71 °F (high). Annual precipitation averages 54 Inches. Marietta 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 | 31.4 °F | 51.5 °F | 4.91 in. |
| February | 34.3 °F | 55.6 °F | 4.82 in. |
| March | 40.6 °F | 63.4 °F | 4.98 in. |
| April | 49.2 °F | 71.6 °F | 4.48 in. |
| May | 58.2 °F | 78.9 °F | 4.19 in. |
| June | 66.1 °F | 84.9 °F | 4.35 in. |
| July | 69.5 °F | 87.8 °F | 5.07 in. |
| August | 68.8 °F | 87.3 °F | 4.04 in. |
| September | 62.7 °F | 82.1 °F | 4.31 in. |
| October | 51.0 °F | 72.6 °F | 3.68 in. |
| November | 39.8 °F | 62.2 °F | 4.27 in. |
| December | 34.4 °F | 53.9 °F | 4.88 in. |
| Annual | 50.5 °F | 71 °F | 53.98 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 |