August in Incheon is the warmest month of the year. In August, the weather in Incheon is typically warm. Average daily high temperature in August is about 27 degrees above zero. On average, Incheon has 16 rainy, 10 sunny, 4 partly cloudy, and 1 cloudy day in August. The rains are usually heavy. August as well as January, February, March, and July is considered the most uncomfortable time to visit Incheon.