Thailand Weather in September

The rainy season is definitely not over yet! Bangkok and its surrounding areas in particular, will endure some fairly extreme weather. The north of Thailand is slightly drier but covered by a layer of clouds. Conditions on Koh Chang in the east will finally start to clear up, though Koh Samui, Koh Phangan, and Koh Tao still have the most chance of sunshine. September is the last month of relatively dry and sunny weather on these islands.

What to expect of the weather in Thailand in September

Bangkok and the surrounding area

September is by far the wettest month for Bangkok and its surrounding areas and the high humidity causes it to feel oppressively warm. Kanchanaburi’s waterfalls will be in full force and once every five years, enough rain falls for the area to flood, making it possible to visit Ayutthaya’s temples by boat.

Ayutthaya – Soak up the culture and visit historical temples.
Bangkok – Thailand’s capital blends old temples with ultra modern skyscrapers.
Kanchanaburi – Town brimming with nature and history.
Khao Yai National Park – The oldest nature reserve with wild elephants.
Koh Samet – White sandy beaches, only three hours from Bangkok.

Koh Samui and the southeastern Gulf of Thailand

September is a great month for this popular group of islands, but expect some heavy rainfall towards the end of the month. September is the last month of great weather in the southeastern Gulf of Thailand. The months of October through to December are Koh Samui, Koh Phangan and Koh Tao’s rainy season. Enjoy the sun while it lasts!

Koh Phangan – Serene island that hosts large beach parties.
Koh Samui – Popular island with long beaches and luxury accommodation.
Koh Tao – Thailand’s number 1 island for snorkeling and diving.

Chiang Mai and the North of Thailand

Though there’s less rain than in August, Chiang Mai is still pretty wet. Temperatures lie between 23 and 32 degrees Celsius, with rainfall occurring mainly in the morning and the late afternoon. In between, it’s mostly cloudy. Great weather to go and explore the green surroundings (rice fields)!

Chiang Mai – A great city surrounded by nature and rich in culture.
Chiang Rai – Gorgeous natural surroundings and best known for the white temple.
Mae Hong Son – Mountain tribes and rice fields near the Burmese border.
Pai – Hippie-at-heart mountain village nestled in Thailand’s most beautiful valley.

Phuket and Krabi

Unless you’re a surfer, the southwest coast of Thailand in September is no place for you! It’s by far the wettest month of the year. Thankfully the worst of the bad weather lasts only a couple of weeks, making way for some occasional, if slightly watery, sunshine in October.

Khao Sok National Park – Wake up in a straw cabin on a clear blue lake.
Koh Jum – Small-scale tourism near Koh Phi Phi.
Koh Lanta – Laid-back atmosphere and nice beaches.
Koh Phayam – Gorgeous but underdeveloped island.
Koh Phi Phi – Thailand’s number 1 tropical party island.
Koh Yao Yai – Big island with long and empty beaches.
Krabi (Ao Nang) – The perfect place to start your island-hopping adventure.
Phuket – Thailand’s largest island, best known for its beaches.

Koh Chang and the Eastern Gulf of Thailand

September will finally see the weather on Koh Chang and its surrounding areas improve. After three months of intense rainfall, the beach weather is on its way back. But… chances of showers remain significant until November.

Koh Chang – Pleasant island with beautiful beaches and a laid-back atmosphere.
Koh Kood – A gorgeous, and partially unspoiled, island.
Koh Mak – Small-scale tourism, laid-back atmosphere.
Koh Wai – Snorkeling island between Koh Chang and Koh Kood.

Koh Lipe and the Trang islands

In September and October weather conditions on Koh Lipe are intense. With an average precipitation rate of 350 millimeters a month, these are by far its wettest months of the year. Besides tropical downpours, expect some serious thunderstorms as well. If you were planning to visit this island and its surrounding areas, it would be best to wait until November.

Koh Lipe – Tropical island, home to Thailand’s most beautiful beaches.
Koh Mook – Small-scale tourism and a spectacular cave.
Koh Ngai – Long golden beaches and no roads.
Koh Tarutao – National park, a former prison island, and camping site.

Isan region

Though rain will persist in Thailand’s northeast, it will gradually decrease. The wettest month (August) is over and the Isan region prepares for the cool season with milder temperatures and less rainfall. The rain does do wonders for the surrounding landscape, however, as it now looks lively and green.

Pha Taem National Park – Ancient murals along the Mekong River.
Phimai – Thailand’s most beautiful Angkor Wat temples.
Ubon Ratchathani – Large city in Isan region with many sights.
Udon Thani – Large city near the Lao border, but famous mainly for its Red Lotus Sea.

Monthly weather overview

January May September
February June October
March July November
April August December