The most pleasant months of the year for Whiteside are June, September and August. In Whiteside, there are 3 comfortable months with high temperatures in the range of 70-85°. July is the hottest month for Whiteside with an average high temperature of 85.9°, which ranks it as warmer than most places in South Dakota. March is the snowiest month in Whiteside with 7.4 inches of snow, and 7 months of the year have significant snowfall. But there some days when the humidity becomes unpleasant, especially in July and August.