May in Ust-Cilma is the rainiest month of the year. In May, the weather in Ust-Cilma is typically cold. Average daily high temperature in May is about 8 degrees above zero. On average, Ust-Cilma has 18 rainy, 7 cloudy, 4 sunny, and 2 partly cloudy days in May. The rains are usually moderate. May as well as January, February, April, and August is considered the most uncomfortable time to visit Ust-Cilma.