In December, the weather in Sendai is typically cold. Average daily high temperature in December is about 5 degrees above zero. On average, Sendai has 17 partly cloudy, 7 rainy, 4 sunny, 2 cloudy, and 1 snowy 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 Sendai.