August in Chillan is the rainiest month of the year. In August, the weather in Chillan is typically warm. Average daily high temperature in August is about 13 degrees above zero. On average, Chillan has 16 rainy, 11 sunny, 3 partly cloudy, and 1 cloudy day in August. The rains are usually heavy. August as well as July is considered the most uncomfortable time to visit Chillan.