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Best Time to Visit Koh Lanta

The Best Time to Dive & Snorkel

Lanta Weather & Climate

When planning your trip, it's important to know when is the best time to visit Koh Lanta, and what to expect from the weather and sea conditions.

The tropical island of Koh Lanta is located close to the mainland Krabi province in southern Thailand, close to Malaysia and Sumatra (Indonesia).

Best Time to Visit Koh Lanta

Koh Lanta sits just 7.6 degrees above the equator and it's tropical climate ranges from warm and wet in the summer to cool and dry in the winter.

Find out all about Koh Lanta, and how to get to Koh Lanta from Krabi, Ao Nang, Koh Jum, Phi Phi, Koh Lipe and Phuket.

When is the Best Time to visit Koh Lanta?

The Koh Lanta diving season is generally the high season months from late October to early May. The wind is mostly from the east, blowing through the South China Sea into the Gulf of Thailand.

The Thai-Malay Peninsula acts as a wind buffer and here on Koh Lanta we usually experience extended periods of sunny days with flat calm seas and little or no rain.

Despite the often great high season weather, we can however occasionally have localised afternoon thunderstorms, with winds sometimes being stronger or changing direction for short periods.

During periods of stronger winds, which can occasionally last for a few days, we may need to change our dive trip schedules.

Water Temperature @ Koh Lanta's Dive Sites

The sea water temperature at most dive sites varies from 28 - 31 degrees throughout the year.

Generally the cooler months are November, December and January, with the hottest and most humid months typically being March and April.

Thermoclines can occasionally drift past, bringing a 'chilly' 26 - 27 degrees for a few minutes underwater. Sometimes we can find less common marine life species in bodies of cooler water.

Lanta Low Season Months

During the typical rainy season months of June to end of September, the westerly monsoon winds from the Indian Ocean bring periods of rain and the occasional storms, however Koh Lanta can also experience long periods of sunshine and calm seas throughout the summer months.

The wettest weather is traditionally in June and September.

Unfortunately the monsoon winds that control Koh Lanta's weather do not change direction on time every year. This means that the rainy season can start later in June, with a break for several months of fine weather and then sometimes start again at the beginning of 'high season' to continue well into January.

Koh Lanta Typical Weather Summary

Month Typical Weather
October: Windy with some rainfall. Improvement in the middle of the month
November: Nice weather with pleasant temperatures, the end of the S/W Monsoon
December: Sunny weather with calm seas and not much wind
January: Sunny weather with pleasant temperatures and clear water
February: Sunny weather with pleasant but higher temperatures and clear water
March: Sunny weather, higher temperatures, calm water with some plankton
April: Hot weather, calm sea with plankton, it might rain at night
May: Hot weather, calm sea with plankton, it might rain at night
June: Start of the S/W Monsoon. Stronger winds, some rainfall and rougher seas
July: Windy, sunny with some rainfall
August: Windy, sunny with some rainfall
September: Stronger winds, rougher seas with some rainfall

Koh Lanta Diving Conditions

Diving conditions vary throughout the year, the best conditions typically being October to early May, though of course the weather can be unpredictable at any time.

Occasionally we can have a few days of stormy weather at some point during the high season months.

Diving in low season is possible, with the best conditions likely between early July and late August.

Diving @ Koh Haa with Dive & Relax

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Visibility @ Koh Lanta's Dive Sites

Visibility varies throughout the year, ranging from 5 - 10m on Koh Phi Phi after stormy weather to 30m+ at Koh Haa and Koh Bida during periods of fine weather.

Currents can bring plankton at any time of year which reduces visibility and makes the water more greenish and this provides food for larger sea creatures. This is important because (for example) we are more likely to see manta ray at Hin Daeng & Hin Muang with greenish water and slight currents than with blue water and 40m+ visibility. Thermoclines can appear at any time and can also affect visibility.

Koh Lanta Weather Forecast

Please remember that the above is only a rough guide based on our observations over the past years.

We don't pretend to be able to forecast the weather and often the weather forecast is wrong (please do not ask us to predict the weather in advance of your trip to Koh Lanta!).

For those of you looking for more information, there are many weather resources on the internet to help with your planning:




Dive Trips & Scuba Courses

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  • Please let us know:

    • when will you arrive on Koh Lanta?
    • your previous dive experience?
    • which diving activities you are interesed in?
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