May in Ust-Kut is the rainiest and the windiest month of the year. In May, the weather in Ust-Kut is typically warm. Average daily high temperature in May is about 10 degrees above zero. On average, Ust-Kut has 14 rainy, 8 cloudy, 5 partly cloudy, and 4 sunny days in May. The rains are usually moderate. May as well as January, February, April, and September is considered the most uncomfortable time to visit Ust-Kut.