When is the best time to go diving on Koh Tao, you ask? Unfortunately, we are afraid there is no definitive answer, as the time that is best for you will depend on your overall wish list for your perfect Koh Tao dive holiday. Important factors include great diving conditions, the chances of seeing particular marine life (most of our customers’ bucket lists include whale shark diving), and of course what the weather will be like on Koh Tao during your stay. After all, not all of your travel group may be here to go scuba diving. Koh Tao has lots of other activities to offer, but dry days are the best for most options.
We are very lucky to have a very agreeable climate for most of the year on Koh Tao. Dive trips throughout the year see water temperature ranges from 26 to 32°C, so no need for lots of neoprene. Most divers find a 3mm. shorty wetsuit is fine, although many simply dive in board shorts and a rash vest. Another advantage of booking a Koh Tao dive holiday is that our wet season is short compared to most other Thailand diving destinations, and even compared to our nearest island neighbors, Koh Phangan and Koh Samui, Koh Tao sees much less rainfall. Air temperature only varies by 10°C all year round, typically sitting between 24 and 32°C – although in humid months it can certainly feel hotter!
To help you with your Thailand dive holiday planning we have put together a yearly overview of Koh Tao diving conditions for you. Of course, there are never any guarantees when it comes to either weather or marine life sightings. But the good news for divers is that there is a large range of dive site options, so it’s generally always possible to select a safe spot for your Koh Tao PADI courses or fun dive trips. Koh Tao’s hilly center means that if one side of the island is experiencing wing or choppy conditions, the other side will have calm and sheltered waters.
It is possible for the end of the wet season to carry on into January, so conditions out at sea can be a little variable and there may be some wind meaning slightly choppy waters. Visibility is considered average, but around new year has historically been a good time for whale shark sightings. Be prepared to share your experience if you are lucky enough to spot one though. January is considered high season, so with more tourists on land, you can expect a few more divers underwater too – especially at the most popular sites.
One of our favorite months for diving on Koh Tao, February brings good visibility underwater and calm surface conditions. It is not too humid on land, but towards the end of the month does get a bit more fiery in the lead up to the hot season. It is still a busy month with tourists taking advantage of the great conditions both below and above water.
Another month where whale shark sightings are possible on Koh Tao dive trips, March marks the beginning of peak heat season. So don’t forget your sunscreen, shades, and hat, as you don’t need to be on the top deck for long before you will burn. It is generally quieter, meaning less traffic on dive sites, and the visibility is still optimal.
The perfect month for those who like it hot! This is usually the driest and hottest month all year in fact. Sunny on land, great visibility underwater and still with a fair chance of a whale shark sighting, this is a popular time for fun divers who have booked Koh Tao dive packages with us. If you like to party, April is definitely a good month for you to visit as Songkran (Thai New Year) is celebrated on April 13th.
In May it is still hot and sunny but starting to cool a little compared to April. It is one of the quietest times around Koh Tao dive resorts and dive sites, making it a favored month for regular Koh Tao scuba lovers. There is still a lingering chance of whale shark sightings, and the ocean is typically calm with good visibility underwater.
June is low season on Koh Tao, so if you want quieter dive sites and also less crowded bars, restaurants, and beaches, then this is a great month to visit. The humidity and high temperatures of peak heat season have dissipated, but with the monsoon season now beginning on the West coast of Thailand (Phuket, Krabi, Koh Phi Phi etc.) it is possible to experience some rainfall.
The start of July remains quiet but from mid to end month our second peak season of the year begins, as European families and backpackers take their summer holidays. Isolated rain showers are still possible and on the surface it is cooler in general than the previous months, yet conditions at sea and underwater remain generally good.
August can be unpredictable and while some years are gloriously sunny and calm, others can be windy, which brings a choppier element to Koh Tao dive trips. You can expect some sporadic rainfall, but any storms are typically quick to blow over. The island is still busy with summer holidaymakers from Europe, and underwater visibility remains above average.
Another of our favorite months! Cooler conditions on land, sunny weather, and calm, flat seas. Plus, the island gets quieter again after the first week once European school and university holidays have come to an end and families and students have returned home. Historically, September is another great month for whale shark sightings, so fingers crossed!
Back when the seasons were a bit more predictable, you could rely on October to be fine for most of the month, with similar conditions to September – including the possibility of a whale shark dive. In the past, the last week of October has been windy as monsoon storms make their way towards Koh Tao, bringing with them waves and reduced visibility. Bear in mind, however, that in recent years wet season has pushed back, and now does not normally arrive until November/December time.
November is the wet season equivalent of May. Low season means quiet streets on land and fewer divers underwater. However, as November is typically when monsoon season has begun, we can’t guarantee good diving conditions. Based on recent years, however, if you take a chance on November diving on Koh Tao, you could beat the odds. For a few consecutive years, November has provided fine weather and dive conditions, and monsoon has not arrived until December.
Depending on what monsoon has decided to do, December can be unpredictable. But in general, you can expect choppier seas, rain, and reduced visibility. That being said, reduced visibility underwater can sometimes be a good thing, and you’ll see more varied marine life as reef inhabitants explore further from their hiding places knowing they cannot be seen so easily by any predators. Plus, diving in December is always fun as around Christmas time as you’ll see many divers in Santa hats, and approaching new year has always been a likely time for whale shark sightings.