August in Oakbrook Terrace is the sunniest month of the year. In August, the weather in Oakbrook Terrace is typically warm. Average daily high temperature in August is about 26 degrees above zero. On average, Oakbrook Terrace has 19 sunny, 7 partly cloudy, and 5 rainy days in August. The rains are usually light. August as well as September is considered the most comfortable time to visit Oakbrook Terrace.