Click on a day for an hourly weather forecast
The temperatures in Koh Samui during May are extremely high, between 28°C and hot as 30°C, drinking water regularly is advisable.
You can expect about 3 to 8 days of rain in Koh Samui during the month of May. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.
Our weather forecast can give you a great sense of what weather to expect in Koh Samui in May 2025.
If you’re planning to visit Koh Samui in the near future, we highly recommend that you review the 14 day weather forecast for Koh Samui before you arrive.
| Month | Temperatures | Rainy Days | Dry Days | Snowy Days | Rainfall | Weather | More details |
|---|---|---|---|---|---|---|---|
| January | 27° / 26° | 8 | 23 | 0 | 326 mm | Good | Koh Samui in January |
| February | 28° / 26° | 3 | 25 | 0 | 87 mm | Perfect | Koh Samui in February |
| March | 28° / 27° | 5 | 26 | 0 | 178 mm | Perfect | Koh Samui in March |
| April | 29° / 28° | 7 | 23 | 0 | 171 mm | Ok | Koh Samui in April |
| May | 30° / 28° | 7 | 24 | 0 | 155 mm | Ok | Koh Samui in May |
| June | 30° / 28° | 9 | 21 | 0 | 184 mm | Ok | Koh Samui in June |
| July | 29° / 27° | 8 | 23 | 0 | 163 mm | Ok | Koh Samui in July |
| August | 29° / 27° | 8 | 23 | 0 | 150 mm | Ok | Koh Samui in August |
| September | 29° / 27° | 10 | 20 | 0 | 188 mm | Ok | Koh Samui in September |
| October | 29° / 27° | 14 | 17 | 0 | 368 mm | Ok | Koh Samui in October |
| November | 29° / 27° | 17 | 13 | 0 | 565 mm | Ok | Koh Samui in November |
| December | 28° / 27° | 11 | 20 | 0 | 368 mm | Good | Koh Samui in December |