August in Daejeon is the hottest month of the year. In August, the weather in Daejeon is typically hot. Average daily high temperature in August is about 30 degrees above zero. On average, Daejeon has 16 rainy, 7 partly cloudy, 5 sunny, and 3 cloudy days in August. The rains are usually heavy. August as well as January, February, July, and December is considered the most uncomfortable time to visit Daejeon.