| 2023 Hardiness Zone: | Zone 7b: 5°F to 10°F Zone 7a: 0°F to 5°F | |
| 2012 Hardiness Zone: | 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: | Cfa - Humid Subtropical Climate | |
| Ecoregion: | 64b - Trap Rock and Conglomerate Uplands | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 31 - 45 days Over 86°F |
Annual Climate Data for ZIP Code 22033 - Fairfax, VA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 23 | 25 | 32 | 41 | 51 | 60 | 65 | 63 | 56 | 43 | 35 | 27 | 43 |
| Avg Max Temp (°F) | 42 | 46 | 55 | 66 | 75 | 83 | 87 | 86 | 79 | 68 | 57 | 46 | 66 |
| Avg Precip (In.) | 3.19 | 2.74 | 3.61 | 3.23 | 4.23 | 3.76 | 3.78 | 3.76 | 4.06 | 3.39 | 3.34 | 3.13 | 42.23 |