August in Fukuoka is the hottest month of the year. In August, the weather in Fukuoka is typically hot. Average daily high temperature in August is about 28 degrees above zero. On average, Fukuoka has 20 rainy, 10 sunny, and 1 partly cloudy day in August. The rains are usually heavy. August as well as January, February, March, and June is considered the most uncomfortable time to visit Fukuoka.