May in Sumon Iymensky is the windiest month of the year. In May, the weather in Sumon Iymensky is typically warm. Average daily high temperature in May is about 12 degrees above zero. On average, Sumon Iymensky has 18 partly cloudy, 9 sunny, 2 rainy, and 2 cloudy days in May. The rains are usually light.