August in Cowes is the rainiest month of the year. In August, the weather in Cowes is typically warm. Average daily high temperature in August is about 13 degrees above zero. On average, Cowes has 24 rainy, 4 sunny, and 3 cloudy days in August. The rains are usually moderate. August as well as May, June, July, and September is considered the most uncomfortable time to visit Cowes.