August in Courmayeur is the sunniest and the warmest month of the year. In August, the weather in Courmayeur is typically warm. Average daily high temperature in August is about 13 degrees above zero. On average, Courmayeur has 18 rainy, 12 sunny, and 1 partly cloudy day in August. The rains are usually heavy. August as well as April, May, June, and July is considered the most uncomfortable time to visit Courmayeur.