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.
September can be a challenging time to visit Thailand as it falls during the rainy season. The weather in Thailand this month is characterized by frequent rainfall, high humidity, and the possibility of tropical storms. If you're planning a trip to Thailand, it's important to have a flexible itinerary and be prepared for occasional heavy downpours that may affect accessibility to certain tourist areas and outdoor activities. Some islands and beaches may also experience rough seas, limiting water-based excursions.
If you're visiting Thailand with kids, consider focusing on indoor attractions like interactive museums in Bangkok, cooking classes in Chiang Mai, or the SEA LIFE aquarium. While outdoor adventures may be limited, this time of year offers lush scenery and fewer crowds. Plus, budget-conscious travelers can take advantage of lower prices on accommodations and flights during this off-peak season.
Khao Sok National Park in Thailand @ Shutterstock
September is one of the wettest months in Thailand, particularly in the south. Bangkok experiences temperatures between 78°F (26°C) and 90°F (32°C) with about 12 inches (300mm) of rainfall. Chiang Mai remains cooler, with highs of 87°F (31°C) and lows of 72°F (22°C).
Phuket, Krabi and Samui are drenched with up to 14 inches (360mm) of rain, but temperatures still range from 77°F (25°C) to 87°F (31°C). Sunshine is reduced to around 4-5 hours per day.
September is one of the best times to visit Thailand for those looking to avoid crowds and take advantage of lower prices, but be prepared for frequent rain. Inland regions like Chiang Rai and the Golden Triangle offer a cooler, less rainy alternative to the coast.
Ang Thong National Marine Park, Thailand © Shutterstock
September is one of the rainiest months in Thailand, especially along the Andaman Coast (Phuket, Krabi, Koh Phi Phi). This keeps tourist numbers low, and prices for accommodations and tours are at their lowest. If you’re looking for the best places to stay in Bangkok, this is a great time to take advantage of discounted rates at top hotels while exploring the city’s temples, markets, and vibrant food scene without the peak-season crowds.
For those heading north, Chiang Mai remains a solid choice, with its cultural sites and mountain landscapes offering a refreshing change from Thailand’s beach destinations. Whether you're interested in temple-hopping or exploring the famous night bazaars, finding the best area to stay in Chiang Mai depends on your travel style — stay in the Old City for history and walkability, or check out the riverside for a more peaceful retreat. Despite the occasional downpour, September’s lower prices and thinner crowds make it a great time to explore Thailand at a slower pace.
Despite the rains, the weather in Thailand in September provides an opportunity to explore © Shutterstock
While going on a trip, one must consider the weather in Thailand in September and the nuances that this month brings. If you're looking for the best places to visit in Thailand during this time, consider destinations like Chiang Mai, Bangkok, or Koh Samui, where the weather is often more manageable.
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.
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.
Meditation in a retreat center © Molfar/Shutterstock
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.
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.
Escape the rain by visiting a traditional Thai retreat center. Many resorts and spas offer wellness packages to relax and rejuvenate.
Khlong Phrao beach on Koh Chang © ronemmons / Shutterstock
There are several festivals and events that take place in Thailand in September. Here's our pick:
San Kamphaeng hot springs, Thailand © Shutterstock
Our Thailand itineraries are crafted to help you experience the best of the country, stress-free. Think of them as a starting point — perfect for planning, but flexible enough to adjust to your own pace and interests. After all, travel is about freedom, but a little planning goes a long way.
