December in Irkutsk is the snowiest month of the year. In December, the weather in Irkutsk is typically freezing. Average daily high temperature in December is about 12 degrees below zero. On average, Irkutsk has 20 cloudy, 8 snowy, 2 sunny, and 1 partly cloudy day in December. The snowfalls are usually light. December as well as January, February, April, and September is considered the most uncomfortable time to visit Irkutsk.