January in Busan is the coldest month of the year. In January, the weather in Busan is typically cold. Average daily high temperature in January is about 7 degrees above zero. On average, Busan has 18 sunny, 7 partly cloudy, 4 rainy, and 2 cloudy days in January. The rains are usually light. January as well as February, March, July, and August is considered the most uncomfortable time to visit Busan.