Mershon, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 12.9 °C (low) to 25.7 °C (high). Annual precipitation averages 1240.5 Millimeters. Mershon 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 | 3.4 °C | 16.7 °C | 104.9 mm |
| February | 4.9 °C | 18.7 °C | 93.73 mm |
| March | 8.1 °C | 22.3 °C | 101.85 mm |
| April | 11.9 °C | 26 °C | 82.04 mm |
| May | 16.3 °C | 29.8 °C | 77.72 mm |
| June | 20.6 °C | 32.2 °C | 151.89 mm |
| July | 22.1 °C | 33.5 °C | 136.4 mm |
| August | 21.9 °C | 32.8 °C | 157.99 mm |
| September | 19.4 °C | 30.5 °C | 107.44 mm |
| October | 13.6 °C | 26.4 °C | 87.88 mm |
| November | 7.7 °C | 21.8 °C | 56.9 mm |
| December | 4.8 °C | 18 °C | 81.79 mm |
| Annual | 12.9 °C | 25.7 °C | 1240.53 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 | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |