July in Koban is the rainiest month of the year. In July, the weather in Koban is typically warm. Average daily high temperature in July is about 22 degrees above zero. On average, Koban has 25 rainy, 5 sunny, and 1 partly cloudy day in July. The rains are usually heavy. July as well as March, April, May, and June is considered the most uncomfortable time to visit Koban.