December in Kushiro is the windiest and the sunniest month of the year. In December, the weather in Kushiro is typically cold. Average daily high temperature in December is about 1 degree above zero. On average, Kushiro has 17 sunny, 8 partly cloudy, 3 rainy, 2 cloudy, and 1 snowy day in December. The rains are usually heavy. December as well as March, April, May, and June is considered the most uncomfortable time to visit Kushiro.