Ashburn, Virginia has a Humid Continental Hot Summers With Year Around Precipitation climate (Köppen classification: Dfa). Average annual temperatures range from 7.2 °C (low) to 19 °C (high). Annual precipitation averages 1131.8 Millimeters. Ashburn is located in USDA Plant Hardiness Zone 7a. 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 | -4.2 °C | 6 °C | 77.22 mm |
| February | -3.3 °C | 7.8 °C | 66.29 mm |
| March | 0.5 °C | 12.6 °C | 95 mm |
| April | 6.1 °C | 19.2 °C | 85.34 mm |
| May | 11.5 °C | 23.7 °C | 114.55 mm |
| June | 16.6 °C | 28.5 °C | 111 mm |
| July | 19.3 °C | 31.1 °C | 106.68 mm |
| August | 18.2 °C | 30.2 °C | 90.17 mm |
| September | 14.4 °C | 26.4 °C | 110.74 mm |
| October | 7.4 °C | 20 °C | 99.31 mm |
| November | 1.6 °C | 13.8 °C | 83.06 mm |
| December | -1.9 °C | 8.2 °C | 92.46 mm |
| Annual | 7.2 °C | 19 °C | 1131.82 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 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 | Dfa - Humid Continental Hot Summers With Year Around Precipitation |