| 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 6a: -10F to -5F | |
| Average First Frost Date: | Oct. 11 - Oct. 20 | |
| Average Last Frost Date: | May 1 - May 10 | |
| Koppen-Geiger Climate Zone: | Dfa - Humid Continental Hot Summers | |
| Ecoregion: | 64d - Piedmont Limestone/Dolomite Lowlands | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | 8 - 14 days Over 86°F |
Annual Climate Data for ZIP Code 17551 - Millersville, PA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 21 | 23 | 31 | 40 | 50 | 59 | 64 | 62 | 55 | 43 | 34 | 26 | 42 |
| Avg Max Temp (°F) | 38 | 41 | 51 | 63 | 73 | 81 | 85 | 83 | 77 | 65 | 53 | 42 | 63 |
| Avg Precip (In.) | 3.33 | 2.46 | 3.39 | 3.36 | 4.22 | 4.06 | 4.29 | 3.38 | 4.13 | 3.32 | 3.42 | 3.15 | 42.5 |