June in Iwakuni is the cloudiest month of the year. In June, the weather in Iwakuni is typically warm. Average daily high temperature in June is about 22 degrees above zero. On average, Iwakuni has 22 rainy, 5 cloudy, 2 sunny, and 1 partly cloudy day in June. The rains are usually heavy. June as well as January, February, March, and July is considered the most uncomfortable time to visit Iwakuni.