Reston, Virginia has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.7 °C (low) to 18.7 °C (high). Annual precipitation averages 1132.6 Millimeters. Reston is located in USDA Plant Hardiness Zone 7b. The growing season typically runs from the last frost around Apr. 21 - Apr. 30 through the first frost around Oct. 11 - Oct. 20.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -3.7 °C | 5.9 °C | 77.47 mm |
| February | -2.9 °C | 7.8 °C | 67.82 mm |
| March | 0.9 °C | 12.4 °C | 97.03 mm |
| April | 6.6 °C | 18.9 °C | 85.6 mm |
| May | 12 °C | 23.4 °C | 113.03 mm |
| June | 16.9 °C | 28.2 °C | 112.52 mm |
| July | 19.7 °C | 30.7 °C | 110.24 mm |
| August | 18.6 °C | 29.7 °C | 89.41 mm |
| September | 14.9 °C | 26 °C | 109.73 mm |
| October | 8.1 °C | 19.6 °C | 96.27 mm |
| November | 2.4 °C | 13.7 °C | 82.04 mm |
| December | -1.4 °C | 8.1 °C | 91.44 mm |
| Annual | 7.7 °C | 18.7 °C | 1132.6 mm |
| Average First Frost Date | Oct. 11 - Oct. 20 |
| Average Last Frost Date | Apr. 21 - Apr. 30 |
| Average Days With Frost | 100-125 Days |
| Plant Hardiness Zone | Zone 7b : -15°C to -12.2°C |
| Plant Hardiness Zone - 2012 | Zone 7a : -17.8°C to -15°C |
| Current Drought Conditions | Moderate Drought |
| Köppen Climate Classification | Dfa - Humid Continental Hot Summers With Year Around Precipitation |