August in Bellevue is the warmest month of the year. In August, the weather in Bellevue is typically warm. Average daily high temperature in August is about 23 degrees above zero. On average, Bellevue has 24 sunny, 6 partly cloudy, and 1 rainy day in August. The rains are usually light. August as well as July is considered the most comfortable time to visit Bellevue.