May in Hua Hin is the hottest month of the year. In May, the weather in Hua Hin is typically hot. Average daily high temperature in May is about 32 degrees above zero. On average, Hua Hin has 19 rainy, 8 partly cloudy, 3 sunny, and 1 cloudy day in May. The rains are usually heavy. May as well as June, July, August, and September is considered the most uncomfortable time to visit Hua Hin.