May in Nakhon Si Thammarat is the rainiest month of the year. In May, the weather in Nakhon Si Thammarat is typically hot. Average daily high temperature in May is about 31 degrees above zero. On average, Nakhon Si Thammarat has 30 rainy and 1 sunny day in May. The rains are usually heavy. May as well as January, April, June, and July is considered the most uncomfortable time to visit Nakhon Si Thammarat.