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 14 rainy, 8 partly cloudy, 7 sunny, and 2 cloudy days in August. The rains are usually heavy. August as well as January, February, March, and April is considered the most uncomfortable time to visit Incheon.