What’s the weather like on Koh Tao?

When you are trying to decide what time of year to visit Koh Tao, the weather on the island will be a major deciding factor. Its location in the Gulf of Thailand, off the Eastern coast of the Thai mainland, means Koh Tao has a sub-tropical climate.

Weather Koh Tao

The island can be hot, humid and sunny all year round and due to its proximity to the equator, receives the same amount of daylight, no matter what season you visit.

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Beautiful Sunset over Chalok Baan Khao Koh Tao

Best time to visit Koh Tao

Koh Tao seasons can be better described by the type of weather rather than the more traditional seasonal definitions; cool & dry, hot & dry, hot & wet and finally, monsoon.

The best time to visit Koh Tao is generally considered to be between January and April, which falls during the dry seasons, but the weather can also be pleasant during the months of July and August.

Whilst Koh Tao has a wet season and a monsoon period, you can experience showers at any time of the year.

They are usually short-lived outside of these times and happen during the night when the ambient temperature is cooler and Koh Tao receives less rain than either Koh Phangan or Koh Samui due to its smaller size.

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Amazing Sunset Facing West on Koh Tao

Types of weather to expect

The weather on Koh Tao can, at times, be a little difficult to predict, but below we have provided a breakdown on what you can expect to encounter during each season.

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Multi-Colored Panoramic Sky on Koh Tao

The Cool & Dry Season – December to February

Koh Tao and the east coast of Thailand, experience their driest period of the year between December and February, as the northwest monsoon has finished.

With both the temperature and the humidity also at their lowest during this period, this is usually the busiest time of the year to visit the island due to the cooler and drier weather conditions.

As would be expected for the driest time of the year, the average monthly rainfall is at its lowest level during this season, however, it has been known for the tail end of the monsoon to continue into December bringing extra rainfall through the month.

On the whole you can expect mostly dry weather with February considered to be the one true dry month that Koh Tao experiences.

The lowest temperatures of the year are experienced during January, although you can still expect daily highs to be around 26 – 28 degrees Celsius.

The humidity will be at its lowest for the year, making the air feel fresher, and the water temperatures will also be at their lowest, usually averaging 27-29°C.

Throughout the dry season you can expect the winds to calm from their peak during the monsoon season and as you head towards the hotter “summer” months, they will drop even further.

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Sunrises on Koh Tao Facing East

The Hot & Dry Season – March to May

With the arrival of the Southwest monsoon during this period, Koh Tao sees the onset of hotter temperatures. You are also likely to experience blue skies on a daily basis making the weather generally very hot and sunny throughout these months.

The temperature on Koh Tao will rise throughout this time, reaching its peak for the year in April, and has been known to hit 40°C on a daily basis. The air is calm and the humidity is also increased.

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Diving Boat Sunset Koh Tao

Great for diving & snorkeling

The water temperature will rise to around 30°C, its hottest throughout the year, and the ocean should remain very calm due to the decrease in the wind, keeping visibility good for diving and snorkeling.

As we move through April and into May, the Southwest monsoon winds arrive in the area and can bring tropical storms.

The amount of rainfall will begin to increase, although the levels will still be considerably lower than during the wet seasons and the showers are generally brief so they shouldn’t impact your ability to enjoy everything Koh Tao has to offer.

Koh Tao remains relatively sheltered from the early parts of the monsoon, due to its location in the Gulf, but you will still be able to watch the spectacular lightning shows and hear the thunder from the storms in the distance that affect the mainland and the ocean in between.

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A Cloudy Day on Koh Tao

The Hot & Wet Season – June to September

The Southwest monsoon winds can be further felt as we move from June through to September. The winds will increasingly become stronger and the air continues to remain hot.

The number of showers the island receives increase as we move closer towards the monsoon, although there should still be lots of periods of hot sunshine between the showers.

The average temperature across this period will be relatively stable, although a little lower than during the summer months. The humidity, however, will be higher and the chance of rain will increase as you move through July and August.

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Paddleboarding on Koh Tao

How much rain can you expect?

As is typical with the sub-tropical climate, the rain generally falls in sudden downpours later in the day but can actually be quite useful in making the air temperature more comfortable in the evening.

The increased chance of rain also means there is an increased chance of the days being cloudy, but you should still be careful to wear sufficient sunscreen as the majority of the suns UV rays will still penetrate the cloud cover, so you can easily become sunburnt without any skin protection.

This period also coincides with the lowest tides on Koh Tao so the beaches are at their widest.

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A Stormy Day around Koh Tao

The Monsoon Season – October to November

Koh Tao only really suffers from the effects of the monsoon during these months, while other areas of Thailand are known to experience the full monsoon from April to October.

The Gulf of Thailand provides a significant amount of protection from the effects of the monsoon. Generally this will reduce the length of the true rainy season to just a few weeks.

The temperatures during monsoon remain in the high 20°C’s

This means the air will feel pleasant and cool. The increased rainfall means the local plant life will be in full bloom so, when the rain stops, the island is crisp and green.

Winds will increase throughout the monsoon period, coming from the north east, and can be particularly high in November. The winds bring the rain with them and the weather becomes much more unpredictable.

Although many of the storms will only last a few hours, the rain has been known to persist for much longer periods during this time. Having said that, it is highly likely to have beautiful sunny days during the monsoon.

The monsoon period also corresponds with the low season in Koh Tao. The visibility for diving is reduced due to the increase in wind and rain and other outdoor activities can be severely impacted by the weather, whilst the higher tides mean that there is less access to the beaches.

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Stunning Sunset on Koh Tao

Flight & Accommodation Deals

Having said that, flights and accommodation can be cheaper at this time of year and the effects of climate change have meant the monsoon may not arrive at all.

Depending on your reasons for visiting Koh Tao, the season you choose can be very important and the information provided above can help you to make an informed decision on when to visit.

It is important to note that the weather on Koh Tao rarely behaves exactly the same year on year so this should be used as a guide to the likely weather conditions you can expect to experience.

You can contact us for up to date weather information and advice on what there is available to do here.

Frequently Asked Questions

When is the best weather on Koh Tao?

Koh Tao has a sub tropical climate and can be hot, humid and dry all year round and due to its proximity to the equator, Koh Tao receives the same amount of daylight each day. It is best to describe the seasons as cool and dry, hot and dry, hot and wet and monsoon, however, the best time to visit Koh Tao is considered to be between January to April and July to August. It is important to note that the weather on Koh Tao rarely behaves exactly the same way each year.

Can I still go diving in November?

Koh Tao is able to offer scuba diving all year round regardless of the weather conditions as the main weather systems arrive from the South West or the North East. As the island is surrounded by protected bays, scuba diving activities can be alternated between either side of the island to offer sheltered conditions. There will be seasonal change in water temperature and visibility, however, water temperature can vary between 25°C to 30°C and visibility from 1metre to 30 metres.

How long does the Monsoon last for?

Monsoon weather in Koh Tao rarely lasts more than a few weeks and it is generally accepted to be in November. It is worth noting that Monsoon weather does not mean continual bad weather for weeks on end, as there will be periods of hot sunshine each day. Rain and squalls may come in unexpectedly and last for a few hours before passing over the island. Occasionally, November may receive no rain at all and the island can often be very hot and dry for 6 months or more before any rain arrives.

Is the temperature warm all year on Koh Tao?

As the island enjoys a sub tropical climate, temperature ranges of between 24°C to 40°C are common all year round. During daylight hours on a typical day, temperatures average around 28°C to 32°C and during the night can drop to 24°C to 26°C.  Temperatures rarely drop below 22°C at any time of the year, day or night.

Does the water get cold?

Koh Tao is a perfect location all year round for water based activities such as, snorkeling, scuba diving, swimming and freediving due to the surrounding warm tropical sea. Water temperatures around Koh Tao average 24°C to 30°C and average 26°C to 28°C for most of the year. If water temperatures start to increase beyond 31°C this can have an impact on the living coral reefs that surround the island and cause coral bleaching.

Do I need to bring warm clothes with me on holiday?

As a visitor to Koh Tao, you will rarely need to wear traditional, warm western clothes due to the sub tropical climate. There may be a use for a light waterproof rain coat, however, you can confidently pack lots of light clothing with appropriate footwear depending on what activities you plan to do. It is always wise to pack one warmer item in case there is a need.