The Best Time to Visit Koh Samui

The Best Time to Visit Koh Samui

Koh Samui is an island in the Gulf of Thailand. Other well-known spellings and names are Ko Samui and Samui. Together with Koh Tao and Koh Phangan and hundreds of other islands, Koh Samui belongs to the Samui archipelago. The second largest island Thailand belongs to the province Surat Thani. Beside Phuket, it is one of the most popular holiday destinations in Thailand, which attracts masses of holidaymakers who are looking for paradise. If you are wondering when the best time to travel to Koh Samui is, you can get all the information you need here. You will receive weather information and a climate table, from which you can get all the data on air and water temperatures, sunshine hours and rainy days. You will learn everything about the dry and rainy season and I will give you many more tips.

When is the best time to go to Koh Samui?

Thailand’s second largest island is a year-round destination. You expect fantastic year-round temperatures of 30 degrees Celsius on Koh Samui. However, there are certain months that are ideal for a holiday. These months are JanuaryFebruary and March which have emerged as the best travel time for Koh Samui. The explanation is simple: during these months the perfect weather is waiting for you.

The temperatures are high but bearable. At night it doesn’t tend to drop below 24 degrees Celsius but don’t worry, your hotel should air conditioning. Another advantage of this season is that there are very few rainy days, so need to worry about lugging an umbrella around with you! February has the fewest day of rain, with only 4 in the entire month! In March it’s five and in January it’s eight days of rain. If you catch a rainy day on your Thailand holiday, you can expect it to rain heavily but only for a short time. During the rainy season on Koh Samui, there are 20 rainy days a month. If you travel to the island in January, February or March, a calm blue sea awaits you, with sun-kissed sands, perfect for topping up your tan!

Koh Samui travel time overview:

    • Best time to visit: January, February, March
    • Optimal but hot time to travel: April to August / September


If you don’t have a problem with high heat, high humidity and a higher probability of rain, you could easily travel in March, April, May, June, July or August. During these months you would have lovely weather on the island, which is why they are also among the best times to travel to Koh Samui.  Swimming in the sea is not a problem either, as the temperature is between 27 and 28 degrees Celsius, as it is throughout the year. The one key disadvantage is the increased chance of precipitation. From April the number of rainy days rises to 13 days and in September can expect around 19 rainy days. In addition, the number of sunny days drops to five a day. But even with rain and fewer hours of sunshine, the midsummer temperatures of 32 degrees are still there.

Best time to go island hopping: Koh Samui, Koh Phangan and Koh Tao

If you are planning a holiday on Koh Samui, then you should also consider including Koh Phangan and Koh Tao in your Thai adventure! Due to the favourable location of the three islands, it is well-worth island hopping with one of the deals on offer. You can decide whether to book a hotel on Koh Samui, Koh Phangan or Koh Tao and explore the sister islands on day trips. Both options have the best travel time in January, February and March. If you sunshine lover, then you could consider island hopping during the hot season (April to September).

Climate and weather on Koh Samui

The island Samui (Koh and Ko means island) is located in the tropical climate zone. The climate is changeable and humid throughout the year. It is around 30 degrees Celsius all year round and for a few months, the temperature reaches 40 degrees Celsius. This is especially true in the months from March to August.

Although there are different seasons on Koh Samui, they are not as distinct as on the mainland. Nevertheless, the three seasons differ in terms of rainy days and only slightly in the air and water temperature. The entire island is under the influence of the monsoon. It ensures that an above-average amount of rain falls from September/October to December. The months of September, October, November and December are therefore considered the rainy season on Koh Samui. In these months it rains on 14 to 20 days. November receives the highest amount of rainfall. It is not uncommon for heavy monsoon rains to occur. The values in November are followed by October and December. Although May does not belong to the rainy season, it can nevertheless be very rainy. The hot season is from March to September. High temperatures, many rainy days and an even higher humidity characterise these months. Temperatures of 40 degrees Celsius are not uncommon. The third season on Koh Samui is called the cool season. It is from November to February and overlaps with the rainy season on Koh Samui. Cool does not mean, however, that there are no summer temperatures. On the contrary. In November, December, January and February, temperatures can reach up to 30 degrees. In the months there are also days when it is cooler, for example only 26 degrees Celsius, but it remains warm with a high humidity.

The seasons at a glance:

Cool season November – February
Hot season March – September
Rainy season September/October – December

Climate table for Koh Samui

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Max. Temperature in °C 29 29,5 31 32 32,5 32 32 32 31,5 31 29,5 29
Min. Temperature in °C 24 25 26 26 26 26 25 25 25 24,5 24 24
Sunshine hours per day 8 7 8 10 8 6 5 5 5 6 7 8
Water temperature in °C 27 28 28 29 29 29 28 28 28 28 28 27
Rainy days per month 8 4 5 13 16 17 16 16 19 20 20 14

Tips for rainy days on Koh Samui

In the months of January, February and March, the number of rainy days is low compared to other months. In the following months, it rises and it rains more often. In November, it rains very often and chances are if you’ve booked your Thai trip for November, you are going to encounter a few downpours! Don’t worry, we’ve come up with a handful of activities you can do if it’s showering outside.

Thai cooking class

On rainy days, for example, a cooking course is really enjoyable as you get to learn about Koh Samui culinary specialities. Once the class is over, feast on your hand-made Thai dishes and spend the afternoon comparing your dishes with all your friends.

Thai Spa

Another way to defy the rainy weather is a wellness day. Koh Samui has great spas and many hotels have their own. If you travel to the island at a rainy time, you can make provisions and directly book a hotel with wellness facilities. Get a massage, do a facial and enjoy the high art of pampering. The Thailandese are well-renowned for their well-being treatments and very soon you’ll forget all about the tropical weather outside.

My conclusion on the best travel time for Koh Samui

For a Thailand holiday on Koh Samui, each season offers different experiences to suit the type of traveller you are. If you want to explore the island at a time of low rainfall, the best time to travel is from January to March. Keep in mind that this is the main travel season for Koh Samui. There are many other holidaymakers from all over the world and therefore you can expect higher hotel and flight prices. The months of April to August are also suitable for hardcore sun worshippers. Just be aware – during this time the temperatures can rise up to 40 degrees Celsius. Nevertheless, the hot season is considered popular by many holidaymakers.

Time to go!

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