December in Kostrovo is the rainiest and the windiest month of the year. In December, the weather in Kostrovo is typically cold. Average daily high temperature in December is about 3 degrees above zero. On average, Kostrovo has 24 rainy, 3 sunny, 2 cloudy, and 2 partly cloudy days in December. The rains are usually moderate. December as well as January, February, March, and October is considered the most uncomfortable time to visit Kostrovo.