August in Cannon Beach is the warmest month of the year. In August, the weather in Cannon Beach is typically warm. Average daily high temperature in August is about 17 degrees above zero. On average, Cannon Beach has 15 partly cloudy, 13 sunny, 2 rainy, and 1 cloudy day in August. The rains are usually light. August as well as July is considered the most comfortable time to visit Cannon Beach.