January in Seosan is the snowiest and the coldest month of the year. In January, the weather in Seosan is typically cold. Average daily high temperature in January is about 1 degree above zero. On average, Seosan has 14 partly cloudy, 13 sunny, 2 rainy, 1 snowy, and 1 cloudy day in January. The rains are usually light. January as well as February, July, and December is considered the most uncomfortable time to visit Seosan.