In May, the weather in Warrnambool is typically warm. Average daily high temperature in May is about 15 degrees above zero. On average, Warrnambool has 13 rainy, 12 partly cloudy, 3 sunny, and 3 cloudy days in May. The rains are usually moderate. May as well as June, July, August, and September is considered the most uncomfortable time to visit Warrnambool.