September in Khao Lak is the coldest month of the year. In September, the weather in Khao Lak is typically hot. Average daily high temperature in September is about 28 degrees above zero. On average, Khao Lak has 28 rainy and 2 cloudy days in September. The rains are usually heavy. September as well as April, May, June, and July is considered the most uncomfortable time to visit Khao Lak.