Pennsylvania planting zones & frost dates
The 6 Pennsylvania cities on this site fall in zones 6b, 7a, 7b. Last spring frost dates range from Apr 4 in Philadelphia to May 2 in Erie.
| City | Zone | Last frost | First frost | Population |
|---|---|---|---|---|
| Philadelphia | 7b | Apr 4 | Nov 11 | 1,573,916 |
| Pittsburgh | 6b | Apr 24 | Oct 22 | 307,668 |
| Allentown | 7a | Apr 26 | Oct 17 | 127,138 |
| Reading | 7a | Apr 21 | Oct 22 | 96,000 |
| Erie | 6b | May 2 | Oct 30 | 92,940 |
| Bethlehem | 7a | Apr 26 | Oct 17 | 79,453 |
Frost dates are 30%-risk dates from the nearest suitable NOAA station. Population: Census Vintage 2024 estimates.