May in Khao Lak is the rainiest month of the year. In May, the weather in Khao Lak is typically hot. Average daily high temperature in May is about 29 degrees above zero. On average, Khao Lak has 30 rainy and 1 sunny day in May. The rains are usually heavy. May as well as January, March, April, and June is considered the most uncomfortable time to visit Khao Lak.