August in Bainbridge Island is the warmest month of the year. In August, the weather in Bainbridge Island is typically warm. Average daily high temperature in August is about 24 degrees above zero. On average, Bainbridge Island has 23 sunny, 7 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 Bainbridge Island.