June in Hamamatsu is the rainiest and the cloudiest month of the year. In June, the weather in Hamamatsu is typically warm. Average daily high temperature in June is about 23 degrees above zero. On average, Hamamatsu has 18 rainy, 8 cloudy, 3 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 Hamamatsu.