In April, the weather in Irkutsk is typically cold. Average daily high temperature in April is about 7 degrees above zero. On average, Irkutsk has 12 rainy, 7 partly cloudy, 6 sunny, and 5 cloudy days in April. The rains are usually light. April as well as January, February, September, and December is considered the most uncomfortable time to visit Irkutsk.