August in Grand Rapids is the sunniest month of the year. In August, the weather in Grand Rapids is typically warm. Average daily high temperature in August is about 23 degrees above zero. On average, Grand Rapids has 16 sunny, 12 partly cloudy, and 3 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 Grand Rapids.