average annual temperature in PA
1 Pennsylvania annual average temperature - 48.77 degrees, 31st warmest state in the U.S. 2  Record Hottest year in Pennsylvania - 1998 / Avg temperature 52.03 degrees. 3  Record Coldest year in Pennsylvania - 1917 / Avg temperature 46.08 degrees. Record Coldest year in Pennsylvania - 1917 / Avg temperature 46.08 degrees. 2  Pennsylvania average Summer temperature (June, July, August) 68.6 F degrees, 34th warmest U.S. summer state.