The most pleasant months of the year for the 15421 zip code are June, September and August. In the 15421 zip code, there are 5 comfortable months with high temperatures in the range of 70-85°. July is the hottest month for the 15421 zip code with an average high temperature of 83.2°, which ranks it as about average compared to other places in Pennsylvania. January is the snowiest month in the 15421 zip code with 12.2 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.