pennsylvania average temperature in spring
1 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. Pennsylvania average Summer temperature (June, July, August) 68.6 F degrees, 34th warmest U.S. summer state. 2  Pennsylvania average Winter temperature (December, January, February) 28.4 F degrees, 20th coldest U.S. winter state.