The Weather and Climate on Koh Lanta: Month by Month Guide

koh lanta weather guide

Koh Lanta, located in southern Thailand’s Andaman Sea, is known for its long beaches, laid-back atmosphere, and stunning marine life. While the island can be visited year-round, the experience changes a lot depending on the season. Understanding Koh Lanta’s weather month by month helps you plan the perfect trip, whether you are looking for calm seas, vibrant festivals, or quieter off-season adventures.

Generally, Koh Lanta has two main seasons:

  • Dry Season (November to April) – Sunny skies, calm seas, and the peak tourist months.
  • Green Season (May to October) – Lush landscapes, occasional heavy rain, and fewer crowds.

Let’s look at the climate and conditions on Koh Lanta, month by month.

January

  • Weather: January is one of the best months to visit. Days are warm (around 28–32°C) with plenty of sunshine and little rain.
  • Sea conditions: Calm seas make it perfect for snorkeling, diving, and boat trips to nearby islands like Koh Rok, Koh Haa, and Koh Phi Phi.
  • Travel vibe: High season, so beaches are lively and accommodations book up early.

February

  • Weather: Another excellent month for visiting, with hot, dry days and cool evenings. Temperatures average 28–34°C.
  • Sea conditions: The water remains crystal clear and flat, great for kayaking, island hopping, or relaxing beach days.
  • Travel vibe: Still high season, though slightly less crowded than December and January.

March

  • Weather: Temperatures start to rise, reaching 30–35°C. Humidity increases but rains are still rare.
  • Sea conditions: Calm seas, excellent visibility for diving and snorkeling.
  • Travel vibe: Still busy, but sunsets get spectacular with vibrant colors.

April

  • Weather: April is hot and humid, with temperatures peaking at 34–36°C. Afternoon thunderstorms may start appearing toward the end of the month.
  • Sea conditions: Seas remain mostly calm, great for water activities.
  • Special events: Songkran Festival (Thai New Year, April 13–15) brings water fights and lively celebrations on the island.

May

  • Weather: May marks the start of the green season. Expect more frequent showers, usually short bursts in the afternoon or evening. Temperatures stay hot at 30–34°C.
  • Sea conditions: The Andaman Sea starts getting choppier. Some smaller tour operators may reduce services.
  • Travel vibe: Fewer tourists, lower prices, and a calmer island atmosphere.

June

  • Weather: June is part of the rainy season, with warm days and frequent but manageable showers. Average temperatures are 28–32°C.
  • Sea conditions: Waves can be stronger, but it’s still possible to enjoy boat trips when the weather clears.
  • Travel vibe: Quiet, peaceful beaches, and excellent deals on accommodation.

July

  • Weather: Rainfall increases, but there are still many sunny intervals. It’s not constant rain; showers usually come in heavy bursts.
  • Sea conditions: Rough seas can make ferry crossings and boat trips less reliable. Swimming is sometimes limited on the west coast beaches.
  • Travel vibe: Off-season charm – you get more of Koh Lanta to yourself.

August

  • Weather: August is wetter, with heavy downpours mixed with sunny breaks. Humidity is high, and temperatures average 27–31°C.
  • Sea conditions: Stronger waves and reduced visibility underwater, making diving less ideal.
  • Travel vibe: Very quiet. Great if you enjoy secluded beaches, but many beachside businesses may be closed.

September

  • Weather: September is typically the wettest month. Heavy rain and storms are common, though not constant. Temperatures remain warm at 27–30°C.
  • Sea conditions: The sea is at its roughest; boat trips are limited.
  • Travel vibe: Very few tourists – the island feels almost deserted.

October

  • Weather: October is a transitional month. Rain still occurs but gradually decreases toward the end of the month. Average temperatures: 28–32°C.
  • Sea conditions: The sea begins to calm, and diving season slowly reopens.
  • Travel vibe: Businesses start reopening, and the island wakes up for the high season.

November

  • Weather: November brings the return of sunshine, clear skies, and pleasant conditions. Temperatures average 28–32°C.
  • Sea conditions: Seas are calm again, perfect for snorkeling and diving.
  • Travel vibe: The season kicks off, with more tourists arriving, but it’s not yet as busy as December and January.

December

  • Weather: December is one of the best months – warm days, little rain, and comfortable evenings. Average temperatures are 27–31°C.
  • Sea conditions: Ideal for all water activities. Diving conditions are excellent, with great underwater visibility.
  • Travel vibe: The holiday season makes Koh Lanta lively. Book accommodation early for Christmas and New Year.

Best Time to Visit Koh Lanta

  • Best overall months: November to April – sunny skies, calm seas, and full access to tours and ferries.
  • For budget and quiet: May to October – fewer tourists and lower prices, but with a chance of rain and limited boat trips.

Practical Tips for Travelers

  • Pack light but prepared: Bring sunscreen, a hat, and light clothing for the hot months. For green season, add a rain jacket and quick-dry shoes.
  • Plan boat trips wisely: Check the weather forecast, especially during May–October. Seas can be rough.
  • Book early in peak months: December to February fills up quickly.
  • Enjoy the green season perks: Lush landscapes, waterfalls flowing, and peaceful beaches await those willing to travel off-season.

Final Thoughts

Koh Lanta is a year-round destination, but the experience shifts dramatically depending on the season. The dry months promise clear skies, calm seas, and lively island life, while the green season offers solitude, dramatic landscapes, and budget-friendly travel. Whether you want to snorkel in crystal waters, join a lively Songkran celebration, or enjoy an empty beach during a rain shower, Koh Lanta has something unique to offer every month.