| 2023 Hardiness Zone: | Zone 7b: 5°F to 10°F Zone 7a: 0°F to 5°F | |
| 2012 Hardiness Zone: | Zone 6b: -5°F to 0°F Zone 7a: 0°F to 5°F | |
| 1990 Hardiness Zone: | Zone 6b: -5F to 0F | |
| Average First Frost Date: | Oct. 11 - Oct. 20 | |
| Average Last Frost Date: | May 1 - May 10 | |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 64a - Triassic Lowlands | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 31 - 45 days Over 86°F |
Annual Climate Data for ZIP Code 20147 - Ashburn, VA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 21 | 23 | 31 | 40 | 50 | 59 | 64 | 62 | 55 | 42 | 33 | 26 | 42 |
| Avg Max Temp (°F) | 42 | 46 | 55 | 66 | 75 | 83 | 88 | 86 | 79 | 69 | 57 | 47 | 66 |
| Avg Precip (In.) | 3.14 | 2.69 | 3.58 | 3.23 | 4.22 | 3.89 | 3.65 | 3.72 | 3.97 | 3.35 | 3.32 | 3.11 | 41.87 |