| 2023 Hardiness Zone: | Zone 7b: 5°F to 10°F | |
| 2012 Hardiness Zone: | Zone 7a: 0°F to 5°F | |
| 1990 Hardiness Zone: | Zone 6b: -5F to 0F | |
| Average First Frost Date: | Oct. 21 - Oct. 31 | |
| Average Last Frost Date: | Apr. 21 - Apr. 30 | |
| Koppen-Geiger Climate Zone: | Cfa - Humid Subtropical Climate | |
| Ecoregion: | 64c - Piedmont Uplands | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 15 - 30 days Over 86°F |
Annual Climate Data for ZIP Code 20851 - Rockville, MD | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 23 | 26 | 33 | 42 | 51 | 60 | 65 | 63 | 57 | 44 | 36 | 28 | 44 |
| Avg Max Temp (°F) | 41 | 44 | 54 | 65 | 74 | 81 | 86 | 84 | 77 | 66 | 55 | 45 | 64 |
| Avg Precip (In.) | 3.32 | 2.85 | 3.88 | 3.25 | 4.39 | 3.76 | 3.92 | 3.74 | 4.12 | 3.42 | 3.43 | 3.22 | 43.3 |