Thailand

Best time to visit Thailand

Most of Thailand shares one season. The Gulf islands do not. This guide gives you the best time to visit for eight destinations in Thailand, using the government's own monthly visitor counts.

When to go to Thailand

The best time to visit most of Thailand is November to February: the cool dry season, with lower humidity and reliable sun. December is the busiest month of the year.

There are two coasts with opposite monsoons. Phuket and Krabi on the Andaman side are wettest from May to October. Koh Samui in the Gulf is wettest from October to December, so November is one of its worst months while the Andaman is at its best. From January to April both coasts are good. Outside that, a trip taking in both means one of them is off-season.

March to May is the hot season, and April is the hottest month. It is also Songkran, which makes April the busiest month of the year in Pattaya and Koh Chang.

September is the quietest month, and also the wettest and the cheapest.

Thailand does not have just one season. It depends on where you go, so one set of months would not fit both the Andaman coast and the Gulf.

Best time to visit by destination

The eight destinations we track, each with its own best months. Note how little Samui shares with the rest.

  • Bangkok November to February The cool season is the one comfortable period for walking the city. April is punishing and September brings the heaviest rain.
  • Phuket November to February The Andaman high season, with the calmest sea and clearest water. Wet from May to October, but busier through it than its reputation suggests.
  • Krabi December to March Same monsoon as Phuket, season starting slightly later. Unusually busy in April for Songkran, quietest in September.
  • Koh Samui February to April The main exception. Gulf coast, so it is dry when the Andaman is wet, and wet from October to December when the Andaman is at its best.
  • Chiang Mai November to February Cool, clear and comfortable in high season. Burning season from late February to April fills the valley with smoke, which is the main reason to avoid spring here.
  • Chiang Rai November to February Cooler and quieter than Chiang Mai, and hit harder by the burning season. September is its quietest month.
  • Pattaya November to February Weekend traffic from Bangkok keeps it busy year-round, and it peaks in April for Songkran rather than December. Wet from June to September.
  • Koh Chang November to February The most seasonal of the eight. April is its busiest month and September its quietest, and plenty of places close for the rainy months.

Green is a month we rate as one of that city's best, amber one worth avoiding.

City JanFebMarAprMayJunJulAugSepOctNovDec
Bangkok Best month 32 Best month 33 Fine 34 Avoid 35 Avoid 34 Fine 33 Fine 33 Fine 33 Avoid 32 Avoid 32 Best month 31 Best month 31
Phuket Best month 32 Best month 33 Fine 33 Fine 33 Avoid 32 Avoid 32 Avoid 31 Avoid 31 Avoid 31 Fine 31 Best month 31 Best month 31
Krabi Best month 31 Best month 32 Best month 33 Fine 33 Fine 32 Fine 32 Fine 31 Fine 31 Avoid 31 Avoid 31 Fine 30 Best month 30
Koh Samui Fine 29 Best month 30 Best month 31 Best month 32 Fine 32 Best month 32 Best month 31 Best month 31 Fine 31 Avoid 30 Avoid 29 Avoid 29
Chiang Mai Best month 30 Best month 33 Avoid 36 Avoid 37 Fine 34 Fine 32 Fine 31 Fine 31 Fine 31 Fine 31 Best month 30 Best month 29
Chiang Rai Best month 29 Best month 32 Avoid 35 Avoid 36 Fine 33 Fine 32 Fine 31 Avoid 31 Avoid 31 Fine 30 Best month 29 Best month 28
Pattaya Best month 31 Best month 31 Avoid 32 Best month 33 Avoid 33 Fine 32 Fine 32 Fine 32 Avoid 31 Avoid 31 Best month 31 Best month 30
Koh Chang Best month 31 Best month 31 Best month 32 Best month 33 Fine 32 Avoid 31 Avoid 30 Avoid 30 Avoid 30 Fine 31 Best month 31 Best month 31

Numbers are the average daily high in °C.

Andaman coast or Gulf coast?

From May to September the Gulf is the better bet, while Phuket is in its rainy months. In October and November it flips, and November is often Samui's wettest month.

Samui stays busy year-round. Its visitor numbers barely move across the year, and Phuket is not much sharper.

  • Andaman (Phuket, Krabi, Khao Lak, Phi Phi): best November to April, wettest May to October.
  • Gulf (Koh Samui, Koh Phangan, Koh Tao): best February to April, with a second drier window June to August. Wettest October to December.
  • Eastern seaboard (Pattaya, Koh Chang): wet from about June to September, and busiest in April for Songkran.

When is the rainy season in Thailand?

The southwest monsoon brings the main rainy season to most of the country from about May to October, with rainfall usually peaking in August or September. Bangkok, the north and the Andaman coast all follow it. The Gulf islands do not, and stay much drier through those months.

Rain is usually heavy and short rather than all day, though some weeks in September are simply wet. Flooding is a real risk in some years, and boats to the smaller islands stop for a day or two in rough weather.

The country does not shut down in the rainy season. It gets cheaper and quieter.

Songkran and the April peak

Songkran, Thai new year, falls on 13 to 15 April and is one of the biggest domestic travel periods of the year. Whole streets turn into a water fight, transport books out, and hotel rates in the party destinations jump.

Pattaya and Koh Chang both reach their yearly peak in April, ahead of the December high season, and Krabi comes close. Domestic travel does that, not foreign visitors.

April is also the hottest month of the year, with highs in the mid to high thirties and heavy humidity. If you want Songkran, book months ahead and accept the heat. After it, domestic travel eases, but April is already hot and the Andaman coast is turning toward its rainy season.

Burning season in northern Thailand

Between roughly February and April, agricultural burning across the north and over the borders fills the air in Chiang Mai and Chiang Rai with smoke. March is usually the worst month.

It is why the north is worth treating separately from the beaches. November to January is excellent up here, cool and clear, with the coolest nights of the Thai year. From late February the haze builds, and by March it can hide the mountain views for weeks at a time.

Visitor numbers follow it. Chiang Mai is busiest in January and falls away through March, and Chiang Rai drops further still. If mountains and clean air are the point of the trip, go before the end of February.

What is the worst time to visit Thailand?

No month is bad everywhere. There are only months that are bad in specific places:

  • September and October on the Andaman coast. The wettest weeks of the year in Phuket and Krabi, and the point where sea crossings get unreliable.
  • October to December in the Gulf. Koh Samui and its neighbors take the northeast monsoon while the rest of the country is entering high season.
  • March and April in the north. Burning season, with the year's worst air quality in Chiang Mai and Chiang Rai.
  • April nationally, if you dislike heat or crowds. Hottest month of the year and the Songkran travel peak on top of it.

The cheapest time to visit Thailand

May, June and September are usually the cheapest months to fly and stay, and September is the emptiest. Rates on the Andaman coast fall a long way from December, and the islands that stay open are quiet in a way they never are in high season.

Those are also the rainy months on the Andaman side. Going to the Gulf in June or July instead gets you dry weather at low-season rates, the best value of the Thai year.

Whatever month you pick, see what a month in Thailand actually costs, and the Thailand money guide for avoiding the 3 to 5% that disappears at ATMs and card terminals.

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Frequently Asked Questions

  • What is the best month to visit Thailand?

    January, for most of the country. It is the middle of the cool dry season, the Andaman sea is calm, and the north is usually clear before burning season peaks. February is the better pick if Koh Samui is on the itinerary.

  • Why are Phuket and Koh Samui good at different times?

    They sit on opposite coasts. Phuket faces west and is wettest from May to October. Koh Samui is in the Gulf and gets its heaviest rain from the northeast monsoon instead, so November is one of its wettest months. January to April suits both.

  • Is the rainy season a bad time to visit Thailand?

    Not for most trips. Rain is usually heavy and short rather than all day, prices fall a long way, and the islands are quiet. The bigger problem is rough seas stopping boats to the smaller islands.

  • When is Songkran and should I avoid it?

    13 to 15 April. Avoid it if you want a quiet trip: April is the hottest month and large numbers of people are traveling. Go for it if a nationwide water fight sounds like fun. It is the busiest month of the year in Pattaya and Koh Chang.

  • When is burning season in Chiang Mai?

    Roughly February to April, worst in March. Burning in the north and across the borders fills the valley with smoke and the air quality gets bad. Come between November and January instead.

  • What is the cheapest time to visit Thailand?

    May, June and September. September is the quietest, and among the cheapest on the Andaman coast. For value without the rain, go to the Gulf islands in June or July: dry then, and still at low-season rates.

  • How far ahead should I book a trip to Thailand?

    Two to three months is enough for most of the year. Book much further out for Christmas and New Year, or for Songkran in mid-April, when domestic and international demand peak together.

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