South Riding, Virginia has a Humid Subtropical Climate climate (Köppen classification: Cfa). Average annual temperatures range from 7.3 °C (low) to 18.9 °C (high). Annual precipitation averages 1123.2 Millimeters. South Riding is located in USDA Plant Hardiness Zone 7a. The growing season typically runs from the last frost around Apr. 11 - Apr. 20 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -4.1 °C | 6.1 °C | 76.96 mm |
| February | -3.2 °C | 7.8 °C | 66.04 mm |
| March | 0.6 °C | 12.6 °C | 94.49 mm |
| April | 6.1 °C | 19.1 °C | 84.58 mm |
| May | 11.6 °C | 23.6 °C | 115.82 mm |
| June | 16.6 °C | 28.3 °C | 111.51 mm |
| July | 19.2 °C | 30.8 °C | 106.68 mm |
| August | 18.2 °C | 29.9 °C | 91.44 mm |
| September | 14.4 °C | 26.3 °C | 105.41 mm |
| October | 7.7 °C | 19.9 °C | 97.79 mm |
| November | 1.9 °C | 13.8 °C | 82.04 mm |
| December | -1.8 °C | 8.2 °C | 90.42 mm |
| Annual | 7.3 °C | 18.9 °C | 1123.18 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 11 - Apr. 20 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7a : -17.8°C to -15°C |
| Plant Hardiness Zone - 2012 | Zone 6b : -20.6°C to -17.8°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Cfa - Humid Subtropical Climate |