Avg weather in May
12 Hrs per day
173 mm per month
71 % avg
3 Mph avg


What’s the weather like in Thailand in May?

Thailand is just to the north of the equatorm which means that most of the country has tropical weather. Temperatures are high all year round, and May’s one of the hottest months of the year although you’ll also have rain as it’s the start of the south western monsoon season. This period has more rain than the north eastern monsoon, and things are also warmer, cloudier and more humid. You’ll still have lots of great beach weather around the country in May though, as it only usually rains for a short time.


Koh Samui is one of Thailand’s most popular islands and has an average high of 32ºC in May. Things stay nice and warm in the evenings, which only cool to 25ºC, so you won’t need to take up much room in your suitcase with warm clothes. You should leave some space for a waterproof top though as there’s 172mm of rain over 15 days. You can still expect six hours of sunshine from the 13 hours of daylight each day. The sea temperature is a warm 30ºC, while humidity’s very high. UV levels will be extremely high so make sure you use plenty of sun cream. Sunset’s just after 6.30pm.

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