December in Bismarck is the snowiest month of the year. In December, the weather in Bismarck is typically freezing. Average daily high temperature in December is about 6 degrees below zero. On average, Bismarck has 18 cloudy, 5 partly cloudy, 4 snowy, and 4 sunny days in December. The snowfalls are usually light. December as well as January, March, April, and November is considered the most uncomfortable time to visit Bismarck.