 The Allegheny Plateau has a continental climate , with occasional severe low temperatures in winter and average daily temperature ranges of 20 ° F ( 11 ° C ) in winter and 26 ° F ( 14 ° C ) in summer . The mean annual precipitation for the Pine Creek watershed is 36 to 42 inches ( 914 to 1 @,@ 070 mm ) . The highest recorded temperature at the park was 104 ° F ( 40 ° C ) in 1936 , and the record low was − 30 ° F ( − 34 ° C ) in 1934 . On average , July is the hottest month at Leonard Harrison , January is the coldest , and June the wettest . 
