The most pleasant months of the year for Slippery Rock University are June, August and September. In Slippery Rock University, there are 4 comfortable months with high temperatures in the range of 70-85°. July is the hottest month for Slippery Rock University with an average high temperature of 82.1°, which ranks it as cooler than most places in Pennsylvania. January is the snowiest month in Slippery Rock University with 11.9 inches of snow, and 6 months of the year have significant snowfall. But there some days when the humidity becomes unpleasant, especially in July and August.