July in Mandurah is the rainiest, the cloudiest, and the coldest month of the year. In July, the weather in Mandurah is typically warm. Average daily high temperature in July is about 16 degrees above zero. On average, Mandurah has 15 rainy, 12 sunny, and 4 partly cloudy days in July. The rains are usually heavy. July as well as August is considered the most uncomfortable time to visit Mandurah.