December in Okushiri is the windiest month of the year. In December, the weather in Okushiri is typically cold. Average daily high temperature in December is about 3 degrees above zero. On average, Okushiri has 9 cloudy, 9 partly cloudy, 8 rainy, 4 snowy, and 1 sunny day in December. The rains are usually heavy. December as well as January, February, March, and April is considered the most uncomfortable time to visit Okushiri.