| 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. 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 21084 - Jarrettsville, MD | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 22 | 24 | 31 | 40 | 50 | 59 | 64 | 63 | 56 | 44 | 35 | 26 | 43 |
| Avg Max Temp (°F) | 40 | 43 | 53 | 64 | 73 | 81 | 86 | 84 | 77 | 66 | 55 | 44 | 64 |
| Avg Precip (In.) | 3.6 | 2.85 | 4 | 3.61 | 4.7 | 4.01 | 4.18 | 3.77 | 4.35 | 3.46 | 3.72 | 3.49 | 45.74 |