Weather history and climate summary information is available for the following locations:
- Allentown
- Erie
- Harrisburg
- Philadelphia
- Pittsburgh
- Pittsburgh (pennsylva)
- Scranton
Warmest May Days
The warmest May days in Pennsylvania are:
| Harrisburg, Pennsylvania | 1996 | 97°F |
| Philadelphia, Pennsylvania | 1991 | 96.1°F |
| Philadelphia, Pennsylvania | 1981 | 95.9°F |
| Allentown, Pennsylvania | 1987 | 93.9°F |
| Philadelphia, Pennsylvania | 1987 | 93.9°F |
Coldest May Days
The coldest May days in Pennsylvania were:
| Scranton, Pennsylvania | 1974 | 25.2°F |
| Scranton, Pennsylvania | 1976 | 25.2°F |
| Pittsburgh (pennsylva), Pennsylvania | 1963 | 27°F |
| Pittsburgh (pennsylva), Pennsylvania | 1977 | 28°F |
| Pittsburgh (pennsylva), Pennsylvania | 1970 | 28°F |
Wettest May Days
The wettest single days in May occurred:
| Allentown, Pennsylvania | 1973 | 11.4 inches |
| Philadelphia, Pennsylvania | 1973 | 11 inches |
| Philadelphia, Pennsylvania | 1981 | 10.4 inches |
| Pittsburgh (pennsylva), Pennsylvania | 1973 | 4.7 inches |
| Scranton, Pennsylvania | 1973 | 4.3 inches |