In August, the weather in Kostomucsha is typically warm. Average daily high temperature in August is about 17 degrees above zero. On average, Kostomucsha has 14 rainy, 8 cloudy, 7 partly cloudy, and 2 sunny days in August. The rains are usually heavy. August as well as January, February, April, and May is considered the most uncomfortable time to visit Kostomucsha.