Pennsylvania frost dates by city
| City | Last frost (50%) | Safer date (10%) | First frost (50%) | Season |
|---|---|---|---|---|
| Allentown | Apr 20 | May 6 | Oct 24 | 184 days |
| Harrisburg | Apr 9 | Apr 25 | Nov 2 | 206 days |
| Philadelphia | Apr 2 | Apr 13 | Nov 10 | 224 days |
| Pittsburgh | Apr 23 | May 12 | Oct 23 | 181 days |
Each city uses its nearest major NOAA weather station, usually the airport. Valleys, hilltops and rural spots can differ from it by one to three weeks. How to read these dates.