| 2023 Hardiness Zone: | Zone 7a: 0°F to 5°F | |
| 2012 Hardiness Zone: | Zone 6b: -5°F to 0°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: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 64c - Piedmont Uplands | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 15 - 30 days Over 86°F |
Annual Climate Data for ZIP Code 21791 - Union Bridge, MD | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 20 | 22 | 30 | 38 | 49 | 58 | 63 | 61 | 53 | 41 | 32 | 25 | 41 |
| Avg Max Temp (°F) | 39 | 44 | 53 | 64 | 74 | 82 | 86 | 84 | 77 | 66 | 55 | 44 | 64 |
| Avg Precip (In.) | 3.37 | 2.66 | 3.73 | 3.47 | 4.39 | 3.98 | 3.53 | 3.4 | 4.02 | 3.5 | 3.48 | 3.21 | 42.74 |