July in Nagano is the rainiest month of the year. In July, the weather in Nagano is typically warm. Average daily high temperature in July is about 23 degrees above zero. On average, Nagano has 27 rainy, 3 sunny, and 1 cloudy day in July. The rains are usually heavy. July as well as March, April, June, and August is considered the most uncomfortable time to visit Nagano.