| 2023 Hardiness Zone: | Zone 8a: 10°F to 15°F Zone 7b: 5°F to 10°F | |
| 2012 Hardiness Zone: | Zone 7b: 5°F to 10°F Zone 7a: 0°F to 5°F | |
| 1990 Hardiness Zone: | Zone 7a: 0F to 5F | |
| Average First Frost Date: | Oct. 21 - Oct. 31 | |
| Average Last Frost Date: | Apr. 11 - Apr. 20 | |
| Koppen-Geiger Climate Zone: | Cfa - Humid Subtropical Climate | |
| Ecoregion: | 65n - Chesapeake Rolling Coastal Plain | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 31 - 45 days Over 86°F |
Annual Climate Data for ZIP Code 21108 - Millersville, MD | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 24 | 26 | 33 | 42 | 52 | 61 | 66 | 64 | 58 | 45 | 36 | 28 | 45 |
| Avg Max Temp (°F) | 43 | 46 | 55 | 66 | 75 | 83 | 88 | 86 | 79 | 68 | 57 | 47 | 66 |
| Avg Precip (In.) | 3.48 | 2.9 | 3.95 | 3.29 | 4.39 | 3.66 | 4.06 | 3.91 | 4.11 | 3.48 | 3.37 | 3.4 | 44.01 |