July in Chilaw is the cloudiest month of the year. In July, the weather in Chilaw is typically hot. Average daily high temperature in July is about 28 degrees above zero. On average, Chilaw has 23 rainy, 7 cloudy, and 1 sunny day in July. The rains are usually heavy. July as well as March, April, May, and June is considered the most uncomfortable time to visit Chilaw.