July in Kumamoto is the rainiest month of the year. In July, the weather in Kumamoto is typically hot. Average daily high temperature in July is about 28 degrees above zero. On average, Kumamoto has 25 rainy, 4 sunny, 1 cloudy, and 1 partly cloudy day in July. The rains are usually heavy. July as well as June and August is considered the most uncomfortable time to visit Kumamoto.