Marietta, North Carolina has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 11 °C (low) to 23.2 °C (high). Annual precipitation averages 1263.1 Millimeters. Marietta is located in USDA Plant Hardiness Zone 8b. The growing season typically runs from the last frost around Mar. 21 - Mar. 31 through the first frost around Nov. 1 - Nov. 10.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | 0.8 °C | 13 °C | 89.15 mm |
| February | 2.1 °C | 14.8 °C | 85.09 mm |
| March | 5.3 °C | 18.9 °C | 91.95 mm |
| April | 9.9 °C | 23.7 °C | 86.61 mm |
| May | 14.9 °C | 27.4 °C | 96.52 mm |
| June | 19.6 °C | 30.7 °C | 125.73 mm |
| July | 21.6 °C | 32.2 °C | 131.06 mm |
| August | 20.8 °C | 31.4 °C | 144.02 mm |
| September | 17.7 °C | 28.5 °C | 145.54 mm |
| October | 11.1 °C | 23.9 °C | 90.68 mm |
| November | 5.3 °C | 18.7 °C | 84.07 mm |
| December | 2.3 °C | 14.6 °C | 92.71 mm |
| Annual | 11 °C | 23.2 °C | 1263.13 mm |
| Average First Frost Date | Nov. 1 - Nov. 10 |
| Average Last Frost Date | Mar. 21 - Mar. 31 |
| 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 | Severe Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |