July in Mackinaw City is the sunniest and the warmest month of the year. In July, the weather in Mackinaw City is typically warm. Average daily high temperature in July is about 22 degrees above zero. On average, Mackinaw City has 18 sunny, 8 partly cloudy, and 5 rainy days in July. The rains are usually light. July as well as August is considered the most comfortable time to visit Mackinaw City.