Thailand's rainy season

When the rains come

The rains run from mid-May to mid-October for most of the country, when the southwest monsoon blows in from the Indian Ocean.

The Thai Meteorological Department declared the 2026 rainy season open on 15 May, with rain in upper Thailand until about mid-October and on the south's east coast until December.

So the rain isn't the same everywhere: it depends on the coast and the month. See our best time to visit Thailand guide for the full year.

Region by region

The rain reaches each region of Thailand at a different time, which is why one coast can be wet while the other is dry.

On Koh Samui, the rain runs from October to January, peaking in November, the Met Office says.

Pick the region for your month, not the other way round.

Ask Tanner which region is dry for your dates.

The rainiest months

August and September are the rainiest stretch for most of Thailand, the second of the two wetter spells in the Thai Meteorological Department's 2026 outlook.

Those are the months to keep the plan flexible.

On the Gulf islands, the rainiest month is November instead.

For a group trip, August and September are the months to plan around, not to avoid entirely: the cities and the Gulf islands still work.

Ask Tanner to keep a spare day in the plan.

Phuket in the rain

The Phuket rainy season runs from May to October, when the southwest monsoon brings choppier seas and red flags to Patong, Kata, Karon and Kamala.

September is the wettest month, with about 361 mm over 23 days, and October comes next.

Rain on Phuket comes in heavy bursts, often in the afternoon, with sunny spells between. Phang Nga Bay is sheltered, so its boat trips are the least likely to be cancelled.

Boat days to Phi Phi can move on choppy days. Phuket's clubs, Bangla Road and the villas carry on. See our Phuket guide.

Ask Tanner for a Phang Nga Bay boat day.

Koh Samui and the Gulf islands

The Gulf islands of Koh Samui, Koh Phangan and Koh Tao run on a different pattern: their heaviest rain comes from October to January, so they're drier while the Andaman coast gets its rain.

So between May and September, the Gulf islands are the drier choice of Thailand's two coasts.

The Full Moon Party on Koh Phangan runs every month, rain or shine; the next ones are 24 November and 24 December 2026.

See our Koh Samui guide and the Full Moon Party guide.

Ask Tanner to put a Full Moon in your trip.

Bangkok in the rain

Bangkok in the wet season is hot and humid, with rain most afternoons, but its rooftops, clubs and malls carry on as usual.

The rain starts in mid-May, and August and September bring the heaviest rain.

Plan outdoor sights for the morning and the evening for the clubs, and keep a car for the group, so nobody waits for a taxi in a downpour.

Licensed clubs in Bangkok's three late zones can stay open until 4am under Ministerial Regulation No. 3, rain or shine (checked November 2026). See our Bangkok guide.

Ask Tanner to keep the car waiting outside the club.

What the rain is really like

Thailand rainy season weather is mostly heavy afternoon or evening showers, not all-day rain.

From mid-May to mid-June, the TMD's outlook said, rain gets heavier and more continuous, especially in the east and on the south's west coast.

Late June to early July often brings a drier spell, and from August to September the rain spreads again.

Pack a light rain jacket and plan the boat days early in the trip, so a wet day can move.

Ask Tanner to make the villa your rain-day base.

Which month to skip?

There's no month to skip Thailand entirely, but September and October are the months to go easy on the Andaman coast, and November the month to avoid the Gulf islands.

In September and October, Phuket and Krabi get their heaviest rain, and some boat days move.

In November, Koh Samui gets its peak rain, while Phuket and Krabi are drying out for the high season.

Match the coast to the month, and every month works. See our where to go in Thailand guide.

What runs, and what cancels

In the wet season, the clubs, rooftops, villas and the Full Moon Party carry on, while some boat trips and national parks close.

Maya Bay on Koh Phi Phi closes for the national park's yearly break from 1 August to 30 September.

Phuket's boat days can move when the sea is choppy, so build a spare day into the plan.

Villa parties, club evenings and spa days work whatever the weather. See villa parties in Thailand.

Ask Tanner what's open in your week.

Is it cheaper?

Yes, the wet season is the cheaper time to visit, with lower prices for hotels and villas, especially on the Andaman coast.

The low season runs from about May to October, the same months as the rains.

For a group, the big costs are the villa, the boat and the club evenings, and villas start from ฿18,500 a day all year.

A full party week for 12 starts from about ฿300,000. See what a Thailand trip costs.

Ask Tanner for the all-in figure for your dates.

A party trip in the rain

A party trip in the wet months works best in Bangkok, Pattaya and the Gulf islands, with a villa as the base and the boat days kept flexible.

Bangkok's clubs and rooftops, a Pattaya pool villa, and a Samui villa with the boat to Haad Rin on Koh Phangan for the Full Moon all carry on through the wet months.

For the boat, pick calmer water: Pattaya's Koh Larn is a short trip, and the Gulf is drier from May to September.

For how the cars work, see VIP transport.

Ask Tanner for a calm-water boat day.

Month by month

The rain looks different in each month, so check the month before you book.

May starts the rainy season, with the heaviest early rain on the Andaman coast. See Thailand in May.

June brings more rain but also the start of the late-June dry spells. See Thailand in June.

August and September bring the widest rain, September is Phuket's wettest month, and October dries out the north while the Gulf islands start their wet season.

Ask Tanner which month suits your group.

Plan around the weather

Pick your month, then the coast that's dry in it: the Gulf islands from May to September, Phuket and Krabi from November.

Then add the villa, the boat and the club evenings, with a spare day for the weather.

Plan it with Tanner, and he sends back the plan for your dates, matched to the coast that's dry.

Thailand's rainy season in short

• The Thailand rainy season runs from mid-May to mid-October for most of the country; the 2026 season began on 15 May.

• August and September are the rainiest stretch for most of the country; September is Phuket's wettest month.
• The Gulf islands flip it: wettest October to January, and drier from May to September.
• Most rain falls in heavy afternoon or evening showers, not all day.
• Clubs, villas and the Full Moon Party carry on all year.
• For the Andaman side, see the best time to visit Phuket.

Checked October 2026.