When is the best time to visit Thailand?

Quick answer by priority

• Best weather overall: December and January. Bangkok averages about 32 to 33°C (90 to 91°F) by day with almost no rain, and Chiang Mai drops to about 15 to 16°C (59 to 61°F) at night.

• Best for Andaman beaches (Phuket, Krabi, Ao Nang, Koh Lanta, Phi Phi): December to March, when monthly rain stays under about 80 mm.

• Best for the Gulf islands (Samui, Phangan, Tao): February to August. Avoid October to December.

• Fewest crowds with acceptable weather: early November and the second half of February into early March, outside the Christmas and Chinese New Year peaks.

• Cheapest: May to October, the southwest monsoon. Rain usually comes as heavy afternoon bursts rather than all-day grey, except on the Andaman coast in September and October.

• Festivals: Songkran on 13 to 15 April 2027, and Loy Krathong with Chiang Mai's Yi Peng lanterns around the November full moon.

• Avoid: the north from about February to April if you are sensitive to smoke, and Bangkok in April if you struggle with heat (average highs around 36°C / 97°F).

Thailand month by month

Figures below are typical averages for Bangkok unless stated, from long-term climate normals. Individual years vary.

• November: about 25 to 33°C (77 to 91°F), rain falling off to about 50 mm. The rains end in the centre and north, crowds build late in the month. Good for Chiang Mai and Loy Krathong; bad for Koh Samui, which is in its wettest month (around 445 mm).

• December and January: about 23 to 33°C (73 to 91°F), almost dry in Bangkok and Chiang Mai. Chiang Mai nights are about 15 to 16°C (59 to 61°F), so bring a layer for Doi Inthanon or Mae Hong Son. Peak prices from about 20 December to early January. This is when our route ran from Bangkok up through Sukhothai, Lampang and Chiang Mai.

• February: about 25 to 34°C (77 to 93°F), still dry. One of the best months for the Andaman and the first good month for the Gulf. The north starts to get hazy.

• March and April: the hot season. Bangkok averages about 35 to 36°C (95 to 97°F) by day, Chiang Mai about 35 to 37°C (95 to 99°F). Beaches still work, especially in March. April is Songkran month.

• May and June: the southwest monsoon arrives. Bangkok gets about 250 mm in May; Phuket about 265 to 295 mm in May and June. Prices drop, the countryside turns green, and the Similan Islands close (16 May to 14 October in the 2026 to 2027 season cycle).

• July and August: about 26 to 34°C (79 to 93°F) in Bangkok with roughly 175 to 220 mm a month. A good window for Koh Samui and Koh Tao, which get only about 100 to 115 mm. European summer holidays push island prices up again.

• September and October: the wettest stretch for Bangkok (about 290 to 335 mm) and the Andaman coast (about 315 to 325 mm). Rough seas cancel some boat trips from Phuket and Krabi. The cheapest weeks of the year; flooding in low-lying areas is possible in some years.

By region: three different rain calendars

Bangkok and the central plains (Ayutthaya, Lop Buri, Sukhothai): dry from November to April, wet from May to October, with September the peak. Ayutthaya and Sukhothai are mostly open-air ruins with little shade, so the heat of March to May matters more than the rain. See our Sukhothai Historical Park guide and day trips from Bangkok.

The north (Chiang Mai, Chiang Rai, Lampang, Mae Hong Son, Pai): the most pronounced cool season in Thailand, with only about 10 to 20 mm of rain a month from November to February. The catch is the burning season, roughly February to April, when crop and forest fires can push air quality to unhealthy levels. Read our Chiang Mai burning season guide before booking March. Our stops at Chiang Mai (22 to 28 December) and Chiang Rai (28 December to 4 January) sat in the middle of the dry, clear stretch. More in where to stay in Chiang Mai and how many days in Chiang Mai.

Andaman coast (Phuket, Krabi, Ao Nang, Khao Sok, Koh Lanta, Phi Phi): the southwest monsoon hits this coast directly, so May to October is wet and seas are rough, while December to March is the clear, calm window. Khao Sok's rainforest and Cheow Lan Lake are easier in the dry months too; we went on from Khao Sok to Ao Nang in mid-January.

Gulf coast (Koh Samui, Koh Phangan, Koh Tao): the pattern is shifted. Summer is relatively dry, and the heaviest rain falls in October to December when the northeast monsoon arrives. If you can only travel in July or August, this is where to put your beach days.

Festivals, holidays and closures in 2027

• Chinese New Year, 6 February 2027: busy in Bangkok's Yaowarat (Chinatown) and in hotels across the country, as visitors arrive from China and the rest of the region.

• Songkran, 13 to 15 April 2027 (Tuesday to Thursday): the Thai New Year water festival. Chiang Mai's water fights around the old city moat usually run longer than the official days. Buses and trains out of Bangkok fill up before it. See our Songkran 2027 guide.

• Similan and Surin Islands: closed each year from mid-May to mid-October; the current cycle reopened on 15 October 2026 and runs to 15 May 2027.

• Loy Krathong and Yi Peng, about 14 November 2027: set by the full moon of the 12th Thai lunar month, so treat it as provisional until Chiang Mai publishes its programme. Our Yi Peng and Loy Krathong guide has the details.

Prices and crowds

Room rates peak from about 20 December to the first week of January, then again around Chinese New Year. In those weeks the islands and Chiang Mai's old city book out first. February is still high season but noticeably calmer after Chinese New Year week.

The best value is the shoulder: early November (rains have ended in Bangkok and the north, beach prices not yet at peak) and late March to April for the Andaman coast if you can handle the heat. On the Gulf islands, July and August combine good weather with lower prices than December, although European families push rates up then.

Domestic trains and buses are the first thing to sell out around Songkran and New Year. If you plan to ride the night train north, read our Bangkok to Chiang Mai sleeper train guide.

When not to go, honestly

Andaman coast in September and October: this is the real low point. Rain averages over 300 mm a month in Phuket, red flags close beaches to swimming, and island-hopping boats from Krabi and Phuket get cancelled. Go to the Gulf instead.

Koh Samui in November: the wettest month there, with around 445 mm on average. Many people book Samui for a December honeymoon and get the tail of this.

Chiang Mai in March and April: hot, with a real risk of smoke haze. If you have a respiratory condition, choose November to January for the north.

The rainy season elsewhere is not a write-off. In Bangkok and the north, June to August usually means a heavy afternoon storm and dry mornings. Temples, markets and food work fine, and you pay low-season prices. For the full six-week route we used, see our Thailand itinerary or the shorter 2-week Thailand itinerary, and our Thailand guide.

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