October is the month the coasts swap. The southwest monsoon lifts off the Andaman side, the Similan and Surin islands reopen on 14 October, and Bangkok and the north start drying out – while the Gulf islands begin their own rainy season as the northeast monsoon arrives. Get the timing right and late October is one of the best-value weeks of the Thai year.
The changeover, in order
October is the only month in the Thai calendar where both monsoon systems are in play, and the sequence matters:
- Early October – still wet almost everywhere. Bangkok around 290 mm, Phuket at its annual wettest at roughly 300 mm, the north still damp.
- Mid-October – Similan and Surin reopen on the 14th, and the Andaman seas begin to settle. Bangkok’s rain starts to taper.
- Late October – northern Thailand is clear and cooling, Bangkok is drying, the Andaman is improving fast, and the high season is about to begin.
- Meanwhile the Gulf – Samui, Phangan and Koh Tao – is going the other way as the northeast monsoon builds towards its November peak.
The practical rule for October: go north or go Andaman, not Gulf. It is the exact inverse of the advice for May to September.
The Similans reopen on 14 October
The Similan and Surin Islands national parks close every year from 16 May and reopen on 14 October. It is a fixed closure set by Thailand’s Department of National Parks for reef recovery, not a weather decision, and the reopening week is a genuine event on the diving calendar – the reefs have had five months without visitors.
Liveaboards for the opening weeks book out well ahead. If a Similan trip is the reason for your trip, the second half of October is the earliest it is possible, and prices are still below the December-to-April peak.
Public holidays and Buddhist Lent ending
- Wednesday 13 October – the anniversary of King Bhumibol’s death, a public holiday and a day of national mourning observed with restraint; some entertainment venues close or tone down.
- Saturday 23 October – Chulalongkorn Day, a public holiday honouring King Rama V.
- Ok Phansa, the end of the three-month Buddhist Lent, falls in October on a lunar date confirmed by the Thai Cabinet. It is one of the five Buddhist holy days with a nationwide ban on alcohol sales, exempting hotels, international airport terminals, licensed venues and designated tourist areas. In the north-east it is marked by the Naga fireball phenomenon on the Mekong at Nong Khai, and by illuminated boat processions.
The Vegetarian Festival
The nine-day Tesagan Gin Je often falls at the turn of September and October, and Phuket’s version – temple processions, firecrackers and the body-piercing rituals – is the famous one. It is genuinely religious rather than staged, it is intense, and for those nine days Phuket is the easiest place in Thailand to eat vegan. Lunar dates, confirmed each year.
Weather by region
- Bangkok – about 31°C with roughly 290 mm across fourteen days, front-loaded into the first half of the month.
- Phuket and the Andaman – about 29°C with roughly 300 mm, its wettest month on paper, but the second half is markedly better than the first.
- Chiang Mai and the north – about 29°C with around 125 mm across nine days, drying and cooling. Late October in the north is excellent.
- Koh Samui and the Gulf – getting wetter as the northeast monsoon arrives, heading for a November peak.
Prices
October is the last cheap month. Rates stay at green-season levels through most of it and begin climbing in the final week as the high season starts. The second half of October – improving weather, reopened marine parks, low-season prices – is one of the best value windows in the Thai year, and it is narrow.
See how much a trip to Thailand costs.
Practical notes
- Book the second half, not the first, if you can choose. The difference across four weeks is substantial.
- Red flags still apply on Andaman beaches early in the month; rip currents ease as the monsoon lifts but do not vanish overnight.
- Bangkok flooding remains possible after early-October storms; the BTS and MRT are the reliable way across the city.
- Loy Krathong is coming – Thailand’s most beautiful festival falls in November. If your trip runs into it, read the November page first.
The October 2027 calendar
- Late September into October – the nine-day Vegetarian Festival; lunar dates.
- Wednesday 13 October – King Bhumibol Memorial Day, a public holiday.
- Thursday 14 October – the Similan and Surin islands reopen for the season.
- Mid-October – Ok Phansa, the end of Buddhist Lent; national alcohol sales ban; Naga fireballs at Nong Khai.
- Saturday 23 October – Chulalongkorn Day, a public holiday.
- Late October – the north clears and cools; high season begins and rates climb.
Read alongside
- Thailand in September – wetter, cheaper, and the Gulf still dry.
- Thailand in November – Loy Krathong and the start of the best season.
- Best time to visit Thailand – all twelve months compared.
- Best islands in Thailand – which coast, and when.
- Koh Samui vs Phuket – October reverses the usual answer.
- How much a trip to Thailand costs – the last cheap month.
- What to pack for Thailand – the changeover list.
Frequently asked
When do the Similan Islands reopen?
14 October, after closing on 16 May. It is a fixed annual closure by Thailand’s Department of National Parks, and liveaboards for the reopening weeks book out well in advance.
Is October a good time to visit Thailand?
The second half is, and the first half is not. Early October is still wet nearly everywhere; by late October the north is clear and cooling, the Andaman is improving fast, the marine parks are open and prices are still at green-season levels.
Phuket or Koh Samui in October?
Phuket, especially late in the month – and this is the one month where that is the right answer. The Gulf islands begin their own rainy season in October as the northeast monsoon arrives, peaking in November.
How wet is Thailand in October?
Bangkok takes around 290 mm across fourteen days and Phuket about 300 mm, its wettest on paper – but both are heavily front-loaded, and the second half of the month is much better. Chiang Mai is already drying, at roughly 125 mm.
What is Ok Phansa?
The end of the three-month Buddhist Lent, on a lunar date in October confirmed by the Thai Cabinet. It is one of five Buddhist holy days with a national ban on alcohol sales, and it is marked by illuminated boat processions and the Naga fireballs on the Mekong at Nong Khai.
Are there public holidays in Thailand in October 2027?
Two fixed ones: King Bhumibol Memorial Day on Wednesday 13 October and Chulalongkorn Day on Saturday 23 October, plus Ok Phansa on a lunar date.
Is October cheap in Thailand?
It is the last cheap month. Green-season rates hold through most of it and start climbing in the final week as high season begins.
Is Chiang Mai good in October?
Late October, very much so – the rains have largely finished, the air is clear, the countryside is still green and the temperature is dropping. It is one of the best windows of the year in the north.
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Written by
John Morrison is the founder and lead travel writer at Packzup. Over the past decade he has explored destinations across Africa, the Americas, Asia, Europe, the Middle East, and Oceania — always self-funded, never on a press trip.
