Manassas, Georgia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 12.6 °C (low) to 25.3 °C (high). Annual precipitation averages 1223.5 Millimeters. Manassas 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 | 2.9 °C | 15.9 °C | 99.06 mm |
| February | 4.4 °C | 17.9 °C | 95.76 mm |
| March | 7.7 °C | 21.7 °C | 97.28 mm |
| April | 11.6 °C | 25.6 °C | 87.38 mm |
| May | 16.4 °C | 29.5 °C | 82.8 mm |
| June | 20.7 °C | 32.3 °C | 141.99 mm |
| July | 22.2 °C | 33.5 °C | 132.59 mm |
| August | 21.9 °C | 32.9 °C | 150.37 mm |
| September | 19.2 °C | 30.3 °C | 94.23 mm |
| October | 13.2 °C | 26 °C | 74.68 mm |
| November | 7.2 °C | 21.1 °C | 67.06 mm |
| December | 4.3 °C | 17.2 °C | 100.33 mm |
| Annual | 12.6 °C | 25.3 °C | 1223.53 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 | Abnormally Dry |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |