June in Ostashkovo is the sunniest month of the year. In June, the weather in Ostashkovo is typically warm. Average daily high temperature in June is about 22 degrees above zero. On average, Ostashkovo has 11 sunny, 11 partly cloudy, and 8 rainy days in June. The rains are usually light. June as well as August is considered the most comfortable time to visit Ostashkovo.