August in Margaret River is the coldest month of the year. In August, the weather in Margaret River is typically warm. Average daily high temperature in August is about 15 degrees above zero. On average, Margaret River has 17 rainy, 10 partly cloudy, 3 sunny, and 1 cloudy day in August. The rains are usually heavy. August as well as June, July, and September is considered the most uncomfortable time to visit Margaret River.