May in Nikolaev is the rainiest month of the year. In May, the weather in Nikolaev is typically warm. Average daily high temperature in May is about 18 degrees above zero. On average, Nikolaev has 18 rainy, 10 sunny, 2 cloudy, and 1 partly cloudy day in May. The rains are usually heavy. May as well as February, March, April, and December is considered the most uncomfortable time to visit Nikolaev.