Best Time to Visit Koh Samui: Weather, Seasons & What to Expect
Koh Samui is a tropical island in the Gulf of Thailand with warm temperatures throughout the year. Unlike other parts of Thailand, Samui follows a slightly different weather pattern, making it a great destination almost year-round, as long as you know what to expect.
The island’s climate is usually divided into three main seasons: dry season, hot season and rainy season. Each season offers a different feel, from peak beach weather to quieter, greener months.
This guide explains Koh Samui’s seasons and helps you decide when is the best time to visit based on how you like to travel.
Dry Season in Koh Samui (December to February)
Best for: Beach days, boat trips, outdoor activities
Average temperatures: 24°C–32°C
The dry season is the most popular time to visit Koh Samui. Days are warm but comfortable, humidity is lower, and rainfall is minimal. This makes it ideal for spending time on the beach, exploring the island and heading out on the sea.
Sea conditions are generally calm, which is why this is a great time for island hopping and snorkelling trips to nearby islands.
Explore our luxury longtail experiences to the southern islands for a relaxed and scenic way to discover Koh Samui’s surrounding waters.
Because this is peak season, accommodation and tours can book up quickly, especially around Christmas and New Year.
Hot Season in Koh Samui (March to August)
Best for: Snorkelling, private boat trips, quieter beaches
Average temperatures: Up to 35°C
The hot season brings long sunny days and warmer temperatures, with March and April usually being the hottest months. While you may experience the occasional short rain shower, these are often brief and followed by sunshine.
The sea remains calm for much of this period, making it an excellent time for snorkelling, diving and private boat experiences. With fewer crowds outside school holidays, it’s a popular choice for travellers looking for a more relaxed pace.
The Ang Thong National Marine Park is an ideal day out in this climate, with calm seas and excellent conditions for exploring the islands.
This season is ideal if you don’t mind the heat and enjoy spending time on the water.
Rainy Season in Koh Samui (September to November)
Best for: Fewer crowds, lush landscapes, better value
Average temperatures: 25°C–30°C
The rainy season in Koh Samui is shorter and more concentrated than in many other areas of Thailand. September and October tend to see the most rainfall, often in heavy but intermittent bursts rather than constant rain.
While some boat trips may be weather-dependent on certain days, there’s still plenty to enjoy on the island. Waterfalls are at their most impressive, the landscape is vibrant and green, and the island feels noticeably quieter.
While sea conditions can vary, quad biking through Koh Samui’s jungle is a great option in almost any weather.
This season suits travellers who are flexible and enjoy a slower, more peaceful version of Koh Samui.
So, When Is the Best Time to Visit Koh Samui?
The best time to visit Koh Samui depends on your travel style and priorities:
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For the best overall weather: December to February
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For snorkelling and boat trips with fewer crowds: March to August
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For a quieter island and better value: September to November
Thanks to its tropical climate, Koh Samui is a year-round destination. With a little planning, you can enjoy the island’s beaches, marine life and experiences in every season.
Come explore with us!
