August in Ann Arbor is the sunniest month of the year. In August, the weather in Ann Arbor is typically warm. Average daily high temperature in August is about 25 degrees above zero. On average, Ann Arbor has 17 sunny, 9 partly cloudy, and 5 rainy days in August. The rains are usually moderate. August as well as {{month_nom: February}}, and {{month_nom: February}} is considered the most comfortable time to visit Ann Arbor.