September in Thailand

September is the height of the green season in Thailand, making it one of the best months to explore the natural attractions in the Thai countryside. As with the other low season months, there are definite advantages to visiting during this quieter time of the year with discounted room rates and promotions on internal flights.

September weather

Although you can expect to see some rain during your trip to Thailand in September, temperatures remain high and you should also experience extended periods of sunny weather.

Location	Avg. Min. Temp. (C)	Avg. Max. Temp. (C)	Avg. Rainfall (mm)
Bangkok	24	32	320
Chiang Mai	23	31	251
Ko Samui	25	32	113
Krabi	25	30	391
Pattaya	25	31	202
Phuket	25	30	417

Where to go in September

For a beach holiday, the Gulf Coast islands of Ko Samui, Ko Tao and Ko Pha Ngan are an excellent choice with plenty of good weather during September, especially in the first half of the month. On the mainland, Chumphon, Hua Hin, Prachuap Khiri Khan and the beaches of Khanom are all solid choices too.

The weather on the Andaman Coast can be variable during September ahead of more settled weather which usually arrives by early October.

On Thailand’s east coast, the beach resorts in Chonburi and Rayong (e.g. Pattaya and Ko Samet) experience lots of sunshine mixed in with occasional showers. Further east, the province of Trat (which includes the islands of the Ko Chang archipelago) is less sheltered than other east coast areas and you can expect mixed weather here. There will be days with sunshine, but you can still expect to see some heavy tropical downpours during September.

In the north of Thailand, the countryside is at its lushest with waterfalls and the scenery particularly impressive during September. This is a fabulous time of year to experience the natural beauty of north Thailand. The historic provincial capitals of Chiang Mai and Chiang Rai make an excellent base to uncover more of the charms of north Thailand. Head into the mountains of Mae Hong Son or enjoy the slow life with visits to laid-back Lampang, Nan and Phrae.

For many areas of Thailand, rivers are in full flow during September and there is the possibility of localised flooding, especially on the flood plains of the Chao Phraya River in central Thailand.

September events and festivals

September marks the start of the longboat racing season in Thailand. This old tradition dates back centuries and takes place during September and October when river levels are at their highest. This is also the Phansa rains retreat period (‘Buddhist Lent’) and is a way for people to pay respects to the rivers which support the local communities. The longboat races take place in various locations around Thailand including Ayutthaya, Phitsanulok, and Nan.

Big waves in Phuket may deter swimmers, but they are welcomed by the surfing community. From July-September, surfing conditions on Phuket can be excellent and local clubs on the island organise a series of events and competitions to take advantage of the waves.

September 28 is designated as Thai National Flag Day. The current design of the ‘thong trai rong‘ (tricolour flag) was adopted on September 28, 1917. The red on the flag represents the land and people, white is for religion and blue is for the monarchy.

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