July in Devonport is the coldest month of the year. In July, the weather in Devonport is typically warm. Average daily high temperature in July is about 11 degrees above zero. On average, Devonport has 13 partly cloudy, 11 sunny, 6 rainy, and 1 cloudy day in July. The rains are usually moderate. July as well as August and September is considered the most uncomfortable time to visit Devonport.