The highest day temperature in May 2025 was 90°F. The lowest night temperature was 83°F. The average values for day and night temperatures during May were 88.2°F и 87.6°F respectivly.

The average sea surface temperature in May 2025 for Samui was 91.3°F. The maximum and minimum values were 90.6°F and 91.8°F respectively.

Most of the days in May are sunny but you can also expect cloudy and gloomy days.

Precipitation total in May for Samui is 3.3 in. It makes may one of the least rainy months of the year.

The average wind speed in May is 8.8 mph. It makes May one of the most windless months of the year for Samui.

We are using day length and cloud cover information for each day of the month to calculate averages for this chart. Average sunny hours for Samui in May is 8.1 hours.