| 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 | |
| 1990 Hardiness Zone: | Zone 7a: 0F to 5F | |
| Average First Frost Date: | Nov. 11 - Nov. 20 | |
| Average Last Frost Date: | Apr. 1 - Apr. 10 | |
| Koppen-Geiger Climate Zone: | Cfa - Humid Subtropical Climate | |
| Ecoregion: | 65n - Chesapeake Rolling Coastal Plain | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 15 - 30 days Over 86°F |
Annual Climate Data for ZIP Code 20634 - Great Mills, MD | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 27 | 29 | 36 | 45 | 55 | 64 | 69 | 67 | 61 | 49 | 40 | 32 | 48 |
| Avg Max Temp (°F) | 45 | 48 | 57 | 67 | 75 | 83 | 88 | 86 | 80 | 69 | 59 | 49 | 67 |
| Avg Precip (In.) | 3.73 | 3.09 | 4.24 | 3.24 | 4.23 | 3.69 | 4.32 | 4 | 4.13 | 3.43 | 3.27 | 3.29 | 44.67 |