| 2023 Hardiness Zone: | 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: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 64c - Piedmont Uplands | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 8 - 14 days Over 86°F |
Annual Climate Data for ZIP Code 21155 - Upperco, 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 | 62 | 55 | 44 | 35 | 26 | 43 |
| Avg Max Temp (°F) | 39 | 43 | 52 | 63 | 73 | 81 | 85 | 83 | 76 | 65 | 54 | 44 | 63 |
| Avg Precip (In.) | 3.47 | 2.83 | 4.08 | 3.55 | 4.61 | 4.03 | 3.9 | 3.49 | 4.24 | 3.46 | 3.55 | 3.46 | 44.68 |