In July, the weather in Hamamatsu is typically warm. Average daily high temperature in July is about 27 degrees above zero. On average, Hamamatsu has 15 rainy, 7 sunny, 5 cloudy, and 4 partly cloudy days in July. The rains are usually heavy. July as well as January, February, March, and June is considered the most uncomfortable time to visit Hamamatsu.