Koh Tao (sometimes called Ko Tao) is a small island located in the Gulf of Thailand which forms part of the Chumphon Archipelago. This island paradise is a popular tourist destination thanks to its idyllic beach scenery and tropical weather – the island experiences over 300 days of sunshine a year.
Koh Tao shares the same sub-tropical climate as the rest of Thailand in that it is dominated by monsoon winds. High temperatures and high rainfall are the main features of this type of climate. The island is affected by both North East and South West monsoons throughout the year.
Travellers should note that although Thailand’s weather is generally tropical all round, Koh Tao and nearby Koh Samui and Koh Phangan sit in the Gulf of Thailand off the east coast of Thailand and their position means that they see different weather conditions to those found off the west coast in the Andaman Sea. For example, in Phuket and the surrounding areas, the rainy season is perhaps more intense and longer than Koh Tao’s, however there is slightly more sunshine.
The weather in Koh Tao can be enjoyable all year round, but depending on what type of climate you prefer, some months may be better suited to your holiday. The weather in Koh Tao can be split into three main seasons: a dry season (between December and February), a hot season (between March and August) and a rainy season (between September and November.) Temperatures do not alter a great deal across the year and it is rainfall that determines the different seasons.
Koh Tao, Thailand.
Dry Season: December – February
Those looking for the best chance of dry weather should plan a trip to Koh Tao between the months of December and February. Rain can never be ruled out on a tropical island, but this period sees the least of it. Heavy showers fall every now and again but usually clear quickly. On average, there’s around 188mm of rainfall in December, falling to 123mm in January and just 39mm in February, the driest month of the year.
This is the most popular time of year to visit the island due to the lack of rain, which also means lots of sunshine and lower humidity levels. Temperatures are still warm at this time of the year, but the lower humidity makes the heat more comfortable. The high temperature sits at around 29°C and the average low gets down to 22°C. This is the coolest time of year, but only slightly.
Sunshine levels are good in Koh Tao’s dry season. The island experiences around seven hours per day, creeping up to eight hours in February, which is perfect weather for relaxing on Koh Tao’s beautiful beaches.
The sea gets down to its coolest for the entire year, falling to just 28°C. However, this is still more than warm enough for swimming and diving, which the island is famous for.
Hot Season: March – August
Between March and August, the South West monsoon hits the region and the weather in Koh Tao changes. These months are hotter and wetter than the dry season, but there are still many clear and sunny days to be enjoyed, especially at the beginning of the season.
Koh Tao is provided some protection from the rain-bearing monsoon winds by the mainland and surrounding islands, so it is less wet than many other parts of Thailand during this season. While March and April are still relatively dry, rainfall increases in May to 172mm, and remains between 118mm and 167mm in June, July and August.
As its name suggests, this is the hottest season on the year in Koh Tao. The average high temperature peaks in April and May at 32°C and it can sometimes get up to 40°C. Even the locals find this exhausting, so if you’re not sure you can cope with the heat, it may be best to visit the island outside of the hot season. Humidity also increases with rainfall, creating stifling and sticky conditions. The sea temperature also increases at this time of year, getting up to 30°C on average.
March and April still see eight bright hours of sunshine each day, but as the season progresses, sunshine levels drop to six hours per day from May onwards.
Wet Season: September – November
In September, torrential downpours, tropical storms and flooding are brought to Koh Tao and the surrounding islands by the North East monsoon winds. This weather lasts until November, and this season is generally the least popular time to visit the island.
Those who do visit in the wet season will see plenty of grey skies and rainstorms, while the amount of good weather is highly unpredictable. In general, it usually rains in the evening and these heavy showers are typically brief leaving many sunny periods, but this is not guaranteed.
With 463mm of rainfall and 20 days of rain, November is by far the wettest month of the year. In fact, it sees almost twice the amount of rain as seen as in October, the second wettest month with 275mm of rainfall.
While the rainfall makes it harder to enjoy Koh Tao’s wonderful beach scene, it does have some advantages. The cooling rain helps to relieve the heat in Koh Tao, and as a result the average high temperature drops to 31°C in September, 30°C in October and 29°C in November. The average temperature is a much more comfortable 27°C. The sea temperature also cools slightly in the wet season, dropping to an average of 29°C, however this is still considered warm by most.
Sunshine levels at this time of year stay around the same as the hot season, with around six hours per day.
Although the wet season is not the best time of year to visit Koh Tao in terms of weather, tourist crowds are much thinner at this time and the island is much more peaceful. In addition, holidays are generally cheaper at this time of year, making it a good choice for budget-conscious travellers.
For more holiday weather information, check our monthly overviews or the current weather forecast for Koh Tao.