May in Pervomayskiy is the rainiest month of the year. In May, the weather in Pervomayskiy is typically warm. Average daily high temperature in May is about 19 degrees above zero. On average, Pervomayskiy has 18 rainy, 11 sunny, and 2 partly cloudy days in May. The rains are usually heavy. May as well as January, February, March, and December is considered the most uncomfortable time to visit Pervomayskiy.