Climate · Koh Samui

Koh Samui in May

Warm and wet, as the days hold steady.

Typical weather, averaged over 30 years

May in Koh Samui is warm: highs near 84°F, lows near 79°F. Rain falls on about five days a week, more often as the month goes on, and daylight holds at about 12 hours 33 minutes.May in Koh Samui is warm: highs near 29°C, lows near 26°C. Rain falls on about five days a week, more often as the month goes on, and daylight holds at about 12 hours 33 minutes.

High
84°F29°Caverage
Low
79°F26°Caverage
Wet days
5a week · 74% of days
Daylight
12h 33mon average

Is May a good time to visit Koh Samui?


May sits outside Koh Samui's best months, which run from January to March. Expect warm days and rain on about five days a week.

How we judge it: every month is scored on how close its typical high comes to the range from 70°F to 80°F, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.How we judge it: every month is scored on how close its typical high comes to the range from 21°C to 27°C, how mild its nights are, and how rarely it rains. The best months are the run of months that scores best.

How May sits in the year

week by week

Temperature

Highs near 84°F in May, against 80°F to 84°F through the year.Highs near 29°C in May, against 27°C to 29°C through the year.

Chance of a wet day

74% of days in May, against 30% to 89% through the year.

Cloud cover

80% cover in May, against 59% to 80% through the year.

Daylight

12h 33m in May, against 11h 35m to 12h 40m through the year.

Week by week, lightly smoothed, with May shaded. The olive line marks the best months. Hover or tap a week for its figures.

Either side


  1. April84°29°low 79°low 26°3 wet days a weekRain on about three days a week.
  2. May84°29°low 79°low 26°5 wet days a weekRain on about five days a week.
  3. June84°29°low 78°low 26°5 wet days a weekRain on about five days a week.

Where Koh Samui sits, in May

Asia/Bangkok

this place
typical high in May 40°F4°C95°F35°C
Sunrise, mid-May
6:00 AMsets 6:33 PM
Above the sea
420 mlow-lying
Latitude
9.5°Nnorthern hemisphere
Nearest of ours
Krabi183 km south-west

The land around Koh Samui, shaded by its typical high in May, the planning map's own layer. Hover the map for the figure at that spot; tap it on a phone. Clock times are local, for the 15th.

Elsewhere in Thailand in May

high · low · wet days

Typical weather, averaged over 30 years (1995–2024), from the 11 km grid square nearest Koh Samui. Temperatures are adjusted against 66 weather stations: daytime highs read about 3.1°F cold in the source data and are raised to match, and both highs and lows are adjusted for the town's height (420 m) against the climate model's (71 m).Temperatures are adjusted against 66 weather stations: daytime highs read about 1.7°C cold in the source data and are raised to match, and both highs and lows are adjusted for the town's height (420 m) against the climate model's (71 m). Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not. Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.

Daylight is calculated from latitude. Charts are lightly smoothed week to week; the figures in the table are not.

Source: Copernicus ERA5-Land reanalysis; cloud cover from NASA's MERRA-2 reanalysis, on a coarser grid of about 50 km. Contains modified Copernicus Climate Change Service information 2026; neither the European Commission nor ECMWF is responsible for any use of it. These are averages, not a forecast.