April in Bismarck is the windiest month of the year. In April, the weather in Bismarck is typically warm. Average daily high temperature in April is about 10 degrees above zero. On average, Bismarck has 13 partly cloudy, 7 sunny, 5 rainy, and 5 cloudy days in April. The rains are usually light. April as well as January, March, November, and December is considered the most uncomfortable time to visit Bismarck.