Weather history and climate summary information is available for the following locations:
- Allentown
- Erie
- Harrisburg
- Philadelphia
- Pittsburgh
- Pittsburgh (pennsylva)
- Scranton
Warmest December Days
The warmest December days in Pennsylvania are:
| Pittsburgh, Pennsylvania | 1982 | 77°F |
| Harrisburg, Pennsylvania | 2006 | 75°F |
| Pittsburgh (pennsylva), Pennsylvania | 1982 | 73.9°F |
| Philadelphia, Pennsylvania | 1998 | 73°F |
| Pittsburgh, Pennsylvania | 2006 | 73°F |
Coldest December Days
The coldest December days in Pennsylvania were:
| Pittsburgh (pennsylva), Pennsylvania | 1989 | -11.9°F |
| Pittsburgh (pennsylva), Pennsylvania | 1983 | -11.9°F |
| Pittsburgh, Pennsylvania | 1989 | -9.8°F |
| Scranton, Pennsylvania | 1989 | -9.2°F |
| Pittsburgh (pennsylva), Pennsylvania | 1951 | -7.6°F |
Wettest December Days
The wettest single days in December occurred:
| Pittsburgh (pennsylva), Pennsylvania | 2010 | 3.2 inches |
| Philadelphia, Pennsylvania | 2008 | 3.1 inches |
| Allentown, Pennsylvania | 1993 | 3 inches |
| Philadelphia, Pennsylvania | 1992 | 3 inches |
| Scranton, Pennsylvania | 1983 | 2.8 inches |