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 4 degrees above zero. On average, Busan has 23 sunny, 5 partly cloudy, and 3 rainy days in January. The rains are usually light. January as well as February, July, and August is considered the most uncomfortable time to visit Busan.