Koh Samui Weather Guide

As you would hope from a tropical island, things can get quite hot and sunny in Koh Samui. Experiencing just 3 seasons annually, here we break down which times are best for the weather and your budget.

Season and Clothing

Dry Season: December to February

Compared to Thailand’s other favourite island, Phuket, the weather in Koh Samui is quite mild. Temperatures are generally warm but rarely reach above 32 degrees Celsius and rain isn’t very common, particularly during the dry season. If rain does fall during this time, it’s usually only in short bursts, bringing with it a breeze that is great for wind surfing. While the weather is reasonably mild all year round, the dry season is considered to be the best time to visit Koh Samui. As a result, accommodation prices during this time are typically high. 

Average temperatures: 24 – 29 degrees Celsius.
Appropriate clothing: Summer clothes, bathing suit and sandals.
Don’t forget: Sunscreen, sunglasses and a hat.

Hot Season: March to June

Things heat up during the hot season in Koh Samui, unsurprisingly! Temperatures typically measure around 28 degrees Celsius, although humidity during this time can be quite high. While the beaches and pools provide fantastic relief from the heat, out of the water air-conditioning will be your best friend during, so be prepared to spend some of your time indoors and off the congested streets. Don't miss Songkran - the annual Thai New Year festivities around mid-April involving much water! If you are heading to the wats (temples), don't forget to cover up.

Average temperatures: 25– 32 degrees Celsius.
Appropriate clothing: Summer clothes, bathing suit and sandals.
Don’t forget: Sunscreen, sunglasses and a hat.

Wet Season: July to November

While the monsoon season hits in July, Koh Samui’s heaviest rain doesn’t fall until October and November. During this time, temperatures and humidity lessen slightly, providing relief from sweltering heat. Typically, the wet season isn’t favoured by tourists so accommodation prices are much lower. If you’re travelling on a budget, this could be a great time to go with breaks between rain providing ample time to see the island’s attractions and showing off inland waterfalls at their best. One of the most popular Thai festivals is also on during early November during the full moon. Loy Krathong gives thanks to the goddess of water by floating banana-leaf vessels filled with candles, coins and other offerings along the river.

Average temperatures: 25 – 31 degrees Celsius.
Appropriate clothing: Summer clothes, bathing suit and sandals.
Don’t forget: Sunscreen, sunglasses and a raincoat.