Thailand weather in September

Wondering about the weather in Thailand in September? In this article we cover everything from average air and sea temperatures to what to look forward to on your Thailand vacation and what to expect.

Is September a good time to visit Thailand?

September can be a challenging time to visit Thailand as it falls during the rainy season. The weather in Thailand in September is characterised by frequent rainfall, high humidity and the possibility of tropical storms. Despite the lush and colourful scenery, outdoor activities may be limited and some islands and beaches can have rough seas. 

Travellers should also be prepared for occasional heavy rainfall and that accessibility to some tourist areas and activities may be reduced. It is advisable to check weather forecasts, plan flexible itineraries and keep an eye on local conditions. On the plus side, travellers looking for less crowded and budget-friendly holiday options can find good deals during this period.

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Canoeing at Khao Sok National Park in Surattani © Shutterstock

Khao Sok National Park in Thailand @ Shutterstock

Air & sea temperatures in Thailand in September

The weather in Thailand in September is characterised by warm temperatures that do not vary much in all regions of the country.

September temperatures in Northern Thailand

September in Northern Thailand is warm, with average temperatures ranging from 24°C to 32°C (75°F - 90°F). The region experiences occasional rainfall and humidity levels become noticeable.

September temperatures in Central Thailand

September is also warm in Central Thailand, with average temperatures ranging from 26°C to 32°C (79°F - 90°F). The region receives a lot of rainfall during this period, which contributes to the overall humidity.

September temperatures in Southern Thailand

September in Southern Thailand remains warm with average highs of 24°C and 31°C (75°F - 88°F). There is occasional rainfall and high humidity in the region, especially in coastal areas.

Sea Temperatures in Thailand in September

Sea temperatures in Thailand's coastal areas in September usually range between 28°C  and 30°C (82°F - 86°F). Travellers should be aware that sea conditions can vary and there is a possibility of rough seas, especially during the rainy season.

Ready to embark on your adventure? Explore our Thailand itineraries for a travel inspiration boost.

Ang Thong National Marine Park, Thailand © Shutterstock

Ang Thong National Marine Park, Thailand © Shutterstock

Can it rain in Thailand in September?

Yes, September is part of the monsoon season in Thailand, especially in the Andaman Sea and Gulf of Thailand areas. During this period, the likelihood of rainfall in Thailand increases. Short, heavy showers and thunderstorms are common, and the rain can be unpredictable.

In the southern and western parts of the country, rainfall is more significant on the west coast. Rainfall may also increase on the east coast, including places such as Koh Samui Island.

You should be prepared for wet weather in Thailand in September. Bring waterproof clothing, make flexible travel plans and be aware of local weather conditions. While it may rain, it often doesn't last all day and there are plenty of indoor activities and attractions to enjoy.

To find the ideal season to visit Thailand for you, make sure to read all about the best time to visit Thailand.

What about the crowd & cost?

September is considered a low season in Thailand due to the monsoon season, resulting in fewer tourists. With less demand for accommodation and entertainment, hotel and tour prices may be more affordable during this period. However, it should be remembered that lower prices are often a trade-off for the greater likelihood of rain and occasional interruptions to outdoor activities.

With fewer crowds, you can enjoy a more relaxed atmosphere at popular tourist destinations, but some beach destinations or smaller islands may have reduced services or temporarily closed access. If you are relaxed about the possibility of rain and are looking for a quieter holiday, September can be a good balance between saving money and seeing the sights of Thailand.

View over Cheow Lan Lake, Khao Sok National Park in southern Thailand © Shutterstock

Despite the rains, the weather in Thailand in September provides an opportunity to explore © Shutterstock

What to wear in Thailand in September?

When visiting Thailand in September, you need to consider the warm and humid climate. Choose light and breathable fabrics such as cotton or linen to stay comfortable in the heat. As this is the monsoon season, also bring a waterproof jacket and an umbrella in case of unexpected rain. It is important to bring comfortable, waterproof shoes and swimwear for a possible visit to the beach or pool. 

Take care of sun protection as well: bring sunscreen, a hat and sunglasses. Also, if you plan to visit temples or conservative places, bring modest clothing that covers your shoulders and knees. It's also a good idea to check the weather forecast just before travelling to choose more weather-appropriate clothing.

 San Kamphaeng hot springs, Thailand © Shutterstock

San Kamphaeng hot springs, Thailand © Shutterstock

Unforgettable and fully customisable Thailand itineraries

Our tailor-made trip service allows you to fully enjoy the weather in Thailand in September without the planning or hassle. All of our itineraries are created by local Thailand travel experts and can be tailored to meet your specific needs.

  • Off the beaten track in Thailand (9 days): From bustling Bangkok to relaxing Chiang Mai, along the way you'll explore towns off the beaten track such as Uthai Thani, Phitsanulok and Lampang where temples, rivers, mountains and local markets are waiting to be discovered!
  • Thailand Luxury Camping (3 days): This trip is the perfect add-on to any trip to Thailand. You'll stay at the Hin Tok River Camp, near Kanchanaburi, one of Thailand's finest tented luxury camps, and explore the surrounding area, including the River Kwai.
  • Family Time in Thailand (15 days): Explore incredible Bangkok city before heading to the verdant Chiang Mai area to meet elephants in their natural habitat. From here, it’s down to the spectacular beach resort of Khao Lak for complete family relaxation.

Or discover more Thailand itineraries.

Meditation in a retreat center © Molfar/Shutterstock

Meditation in a retreat center © Molfar/Shutterstock

What to do in Thailand in September

While going on a trip, one must consider the weather in Thailand in September and the nuances that this month brings. You may also be interested in our list of the best things to do in Thailand at any time of year.

Go monsoon kayaking in Ao Thalane

In September, embark on a thrilling monsoon kayaking adventure at Ao Talan in Krabi. Soak up the rain as you paddle through enchanting mangrove forests and towering limestone cliffs. The rainy season offers a unique perspective as the landscape is adorned with lush greenery.

Explore Krabi Hot Springs and rainforest

Experience the natural wonders of Krabi in September with a visit to Klong Thom Hot Springs. Enjoy the therapeutic benefits of thermal pools surrounded by lush rainforests.

Go island-hopping in Koh Chang

Despite the rain, explore the lush landscapes and waterfalls of Koh Chang Island. Take advantage of the reduced number of tourists and enjoy the serene beauty of this tropical island.

Enjoy Thai cookery classes

Avoid the rainy weather by taking part in a Thai cooking class. Learn to prepare traditional dishes and learn Thai cooking techniques with a unique indoor class.

Visit traditional Thai retreat

Escape the rain by visiting a traditional Thai retreat centre. Many resorts and spas offer wellness packages to relax and rejuvenate.

Khlong Phrao beach on Ko Chang © ronemmons / Shutterstock

Khlong Phrao beach on Koh Chang © ronemmons / Shutterstock

Planning your September trip to Thailand

For more inspiration, read about Thailand's beaches and islands and start planning your trip with The Rough Guide to Thailand

Daunted by the prospect of planning? No problem! Browse our customisable Thailand itineraries, and talk to our local Thailand travel experts.

Visit Thailand in other months

Olga Sitnitsa

written by Olga Sitnitsa

updated 29.12.2023

Online editor at Rough Guides, specialising in travel content. Passionate about creating compelling stories and inspiring others to explore the world.

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