August in Eastham is the warmest month of the year. In August, the weather in Eastham is typically warm. Average daily high temperature in August is about 22 degrees above zero. On average, Eastham has 16 sunny, 9 partly cloudy, 5 rainy, and 1 cloudy day in August. The rains are usually moderate. August as well as July is considered the most comfortable time to visit Eastham.