December in Ostashkovo is the windiest month of the year. In December, the weather in Ostashkovo is typically freezing. Average daily high temperature in December is about 11 degrees below zero. On average, Ostashkovo has 20 cloudy, 9 snowy, and 2 sunny days in December. The snowfalls are usually light. December as well as January, February, and October is considered the most uncomfortable time to visit Ostashkovo.