Koh Samui, Thailand Weather and Climate

Geographical location

Short for USM by abbreviationfinder, Koh Samui (other spellings: Ko Samui or just Samui) is, together with the island of Phuket, one of the most popular holiday destinations in Southeast Asia and is the third largest island in Thailand with around 240 km².

In the vicinity of other paradises such as Ko Tao, the palm-fringed Koh Samui is sheltered in the Gulf of Thailand and delights travelers from all over the world with its fantastic beaches and excellent hotel resorts.

The island is part of the so-called Samui archipelago together with around 100 islands from Koh Phangan to the Ang Thong Islands. The airport of Koh Samui is located in the northeastern part, a ring-shaped coastal road connects all regions.

In the southwest, Khao Thai Kwai, the highest mountain on Koh Samui, towers over 630 meters, despite the tourism boom in Thailand there are still sleepy villages, small fishing ports and lots of idyll.

The most popular and liveliest vacation spots on Koh Samui are Chaweng on the east coast and Lamai on the south of the island. Thailand tours usually start from Bangkok and combine the inland areas such as Chiang Mai and Chiang Rai in the north at the end with a swim on Phuket, Koh Samui or one of the smaller islands.

Climate on Koh Samui

In contrast to many other regions in Thailand and the entire region of Southeast Asia, Koh Samui can be described as a year-round destination with few exceptions, with temperatures only dropping below 23 ° C even at night in the supposedly “cooler” season.

In fact, up to three different seasons can be found on Koh Samui, but you cannot compare the differences with the seasons in Europe. The rainy season on Koh Samui lasts from about mid- September to December, the climate is now very humid and the weather can be especially in November and December very moody. Longer monsoon rain showers and sometimes strong storms can affect the holiday at this time.

However, you might as well be lucky and encounter some fantastic weather (at low low season prices). At the latest at the turn of the year it will be significantly drier, from March the hot season will begin, and there is now almost no wind. With May there are again more days with rain showers, whereby it is more a question of welcome refreshments from above.

When to go to Koh Samui

If you want to be on the safe side, avoid the rainiest months on Koh Samui. By far the most rain falls in November, followed by October, December and May. Nevertheless, especially during the supposed rainy season, fantastic bargains lure on Thailand’s islands, but you should be aware of the risk that the holiday could fall into the water.

Basically, the months of January to March are considered the best time to travel to Koh Samui. But even the much hotter months April to September can be recommended as a travel time despite several rainy days.

The tropical climate ensures hot temperatures and quite high humidity all year round. By the way, most tourists come – due to the European summer holidays – between July and the beginning of September, so please don’t get us wrong: You can also experience an unforgettable holiday on Koh Samui in summer!

Temperatures, precipitation, sunshine in Na Thon (Koh Samui)

Jan Feb March Apr May Jun Jul Aug Sep Oct Nov Dec
Daytime temperature 29 ° C 30 ° C 31 ° C 32 ° C 33 ° C 32 ° C 32 ° C 32 ° C 32 ° C 31 ° C 30 ° C 29 ° C
Night temperature 24 ° C 25 ° C 26 ° C 26 ° C 26 ° C 26 ° C 25 ° C 25 ° C 25 ° C 25 ° C 24 ° C 24 ° C
Water temperature 27 ° C 28 ° C 28 ° C 29 ° C 29 ° C 29 ° C 28 ° C 28 ° C 28 ° C 28 ° C 28 ° C 27 ° C
Precipitation in mm 144 33 51 86 158 93 131 106 113 266 526 213
Rainy days 8 4 5 13 16 17 16 16 19 20 20 14
Hours of sunshine 8 7 8 10 8 6 5 5 5 6 7 8
Sunrise 6:40 6:40 6:30 6:10 6:00 6:00 6:05 6:10 6:10 6:10 6:15 6:30
Sunset 18:20 18:30 18:30 18:30 18:35 18:40 18:45 18:40 18:20 18:05 17:55 18:00


The annual average temperature in Na Thon is 28 ° C. For comparison: Munich reaches an average of 8.6 ° C, in Berlin it is 9.6 ° C. The warmest month is April (29.2 ° C), coldest month of December with averages of 26.5 ° C. The maximum water temperature in Na Thon is 29 ° C. Comfortable bathing is possible at these temperatures. All months have a water temperature of at least 21 ° C and are therefore suitable for a beach holiday.


The annual precipitation is 1920 mm on 168 days with precipitation. For comparison: In Munich, 967 mm, in Berlin 570 mm, precipitation is measured annually. The months of October, November and December are considered the rainy season, as more than 175 mm of precipitation can be expected per month. Overall, about 1005 mm of precipitation can be expected in the rainy season. You cannot expect snow in any month in Na Thon.


As our climate table shows, April is the sunniest month with an average of 9.7 hours of sunshine per day. On average over the year the sun shines 6.9 hours per day. For comparison: In Munich and Berlin, the sun shines an average of 4.7 hours per day throughout the year.

Cities nearby

The following larger towns are nearby and have a similar climate: Surat Thani.

Sights and highlights

Similar to Phuket and Koh Phangan, Koh Samui is especially popular with bathers, but the island in the Gulf of Thailand has much more to offer than just lying on lazy skin under the sun. Despite the high temperatures, the great weather also allows for unforgettable excursions:

The sights of Koh Samui include, for example, the Big Buddha with a height of 12 meters and the inspiring temple complex Wat Plai Laem, and the mummified monk in Wat Khunaram is also worth a visit. In Lamai, not only are the bizarre rock formations waiting under the open sky, but also a magnificent viewpoint above Lamai Beach.

A tour to the Na Mueang waterfall should not be missing on any Koh Samui trip, especially in the rainy season, huge masses of water rush down here. Boat trips to the famous Angthong National Marine Park are also very popular. Our recommendations for the most beautiful beaches on Koh Samui:

Silver Beach has long since ceased to be an insider tip and is as heavily frequented as Lamai and Chaweng Beach. Instead, go to the incomparable Maenam Beach, Bang Po Beach or Choeng Mon Beach. Despite the risk of confusion, Chaweng Noi Beach is also worth recommending!

Koh Samui weather in March, April and May

Daily temperatures averaging 31 to 33 ° C can be expected over the next three months. The temperatures hardly fluctuate during this time.

Do you want to go on a beach holiday? The water temperatures are in March, April and May 28-29 ° C. This is great weather for a great time on the beach and in the water.

The expected rainfall is around 5 days in March, around 13 days in April and around 16 days in May.

In the period from March to May the sun shines on average between 8 and 10 hours a day. The sunniest weather is in Na Thon in April, but with less sun you will have to get by in March.

Koh Samui, Thailand

Koh Samui, Thailand Weather and Climate
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