August in Kostiantynivka is the sunniest and the warmest month of the year. In August, the weather in Kostiantynivka is typically hot. Average daily high temperature in August is about 28 degrees above zero. On average, Kostiantynivka has 24 sunny, 6 partly cloudy, and 1 rainy day in August. The rains are usually moderate. August as well as September is considered the most comfortable time to visit Kostiantynivka.