August in Rayakoski is the sunniest month of the year. In August, the weather in Rayakoski is typically warm. Average daily high temperature in August is about 13 degrees above zero. On average, Rayakoski has 14 rainy, 7 cloudy, 6 sunny, and 4 partly cloudy days in August. The rains are usually moderate. August as well as January, April, May, and June is considered the most uncomfortable time to visit Rayakoski.