August in Kupiansk is the sunniest month of the year. In August, the weather in Kupiansk is typically warm. Average daily high temperature in August is about 27 degrees above zero. On average, Kupiansk has 21 sunny, 7 partly cloudy, 2 rainy, and 1 cloudy day in August. The rains are usually light. August as well as September is considered the most comfortable time to visit Kupiansk.