August in Stellenbosch is the rainiest month of the year. In August, the weather in Stellenbosch is typically warm. Average daily high temperature in August is about 15 degrees above zero. On average, Stellenbosch has 17 sunny, 9 rainy, 4 partly cloudy, and 1 cloudy day in August. The rains are usually heavy. August as well as June and September is considered the most uncomfortable time to visit Stellenbosch.