It comes as no surprise that Thailand’s second-largest island, Koh Samui, attracts millions of tourists each year. Being aware of the weather and seasons here can help determine the optimal time to travel to and explore the attractions of this region, especially if you are a lover of the great outdoors. 

With plenty of sea, sand and surf, the island has much to offer for those looking to enjoy a tropical vacation. Thankfully, much of the year is suitable for travellers looking to travel here and have fun. 

Seasons of Koh Samui

Much like the rest of Thailand, Koh Samui has a tropical savannah climate. Here there are three distinct seasons to be expected. These include the dry season, hot season and rainy season. 

Dry Season

The dry season runs from around December to February.  During this time the, Koh Samui enjoys slightly cooler temperatures with little rain. The wind is moderate, which can make for little surf. However, there are many other water activities to be enjoyed including kayaking, paddle boarding, snorkelling, scuba diving and big game fishing.

The calm drier weather is considered the best option for many travellers, also making this the peak tourist season for the island.

Hot Season

Koh Samui’s hot season comes next, running from March to August. It is the longest-running season, with temperatures rising more than during the dry season, often being hot and sunny. Also, a good time to travel to the island, especially for those that love to have fun in the sun. Temperatures will often soar above 30°c, with minimal cloud coverage. If you intend to travel at this time, remember to keep well hydrated and slather on plenty of sunscreen.  

Wet/Rainy Season

This is the least popular tourist season, likely because it is the least sunny. Although classified as a wet season due to the more frequent rain showers, the rain is really not that much and tends to be short-lived. This means you will find that it rains for a short period of the day, with the rest being dry and sunny. The wettest month during this period is usually November, while the whole season runs from September to November. 

Even during peak monsoon weather, this rainfall will often last less than an hour. While some places can get muddy, the region does not have much of a history of flooding. There is however more humidity to contend with and more cloud cover than the rest of the year. 

Budget travellers appreciate this period as it means fewer tourist numbers and often lower rates. To entice more travellers, many hotels will offer great off-peak deals around this time that you should capitalise on if you are on a tight budget. 

Water Temperature

Generally, Koh Samui’s weather is conducive for travel, pretty much all year round. This is partly thanks to the mostly dry and warm weather, even during the wet season. The fairly consistent water temperature of 29°c is also a big plus. 

This balmy warmth to the surrounding waters of the Gulf of Thailand means that you can comfortably enjoy all manner of fun water activities that Koh Samui is known for. Amongst the island’s notable water activities are snorkelling, scuba diving, freediving, kitesurfing, speed boating, fishing, and paddleboarding. 

Underwater activities like snorkelling and scuba diving are must-try thanks to the abundance of marine life there is to discover. From the whale sharks at Ko Tao to the vibrantly coloured schools of fish at Coral Cove, there is much to discover, whether you are an expert swimmer or a novice looking to make your first trial at underwater exploration. 

Top Tips for Travellers

Be aware of what kind of weather you will deal with depending on what time of year you travel to Koh Samui. Be sure to always wear adequate sunscreen (SPF50 at least), wear a wide-brimmed hat and hydrate. If you do take advantage of the great off-peak deals during the wet season, do not be despondent just because it rains. 

You can easily explore and enjoy attractions that are further inland including visiting temples, hiking, visiting parks, elephant trekking, and spas. Thrill-seekers can also try zip-lining through mountain forests, paragliding or some off-roading. Keep in mind that even during the wettest periods, actual rainfall lasts a short period and you will quickly be able to head out on new adventures. 

If you love food and shopping, the local markets at Fisherman’s village Walking street and Lamai Walking Street are a wonderful opportunity to secure some great bargains on souvenirs and indulge in some delicious and cheap food. 

Whatever time of year you choose to travel to Koh Samui you are assured of having plenty of options for having fun. No matter the weather. So choose a time that is most conducive to you and you will not be disappointed.