January in Kostomarovka is the snowiest, the cloudiest, and the most freezing month of the year. In January, the weather in Kostomarovka is typically freezing. Average daily high temperature in January is about 13 degrees below zero. On average, Kostomarovka has 12 cloudy, 7 snowy, 7 partly cloudy, and 5 sunny days in January. The snowfalls are usually light. January as well as February and December is considered the most uncomfortable time to visit Kostomarovka.