Best Time to Visit Thailand

The table above is Bangkok. The rest of the country runs on different clocks, and the mistake first-timers make is reading “rainy season” as a single nationwide event.

• Andaman coast (Phuket, Krabi, Khao Lak, Phi Phi, Ko Lanta, Ko Lipe): dry and calm from November to April, wet from May to October with the roughest seas in September and October. The Similan and Surin marine parks close completely from mid-May to mid-October, and smaller speedboat routes such as Ko Lanta to Ko Lipe stop running. Maya Bay on Phi Phi closes every August and September to let the reef recover.
• Gulf islands (Ko Samui, Ko Pha-ngan, Ko Tao): the opposite rhythm. Heavy rain falls from October to December, with November usually the wettest month on Samui, and the islands are mostly dry from January to August with only short mid-year showers. This is where to go in June, July and August when the Andaman is wet.
• Eastern seaboard (Pattaya, Ko Samet, Ko Chang, Hua Hin across the gulf): follows the Bangkok pattern, dry November to April and wet May to October. Ko Chang’s steep hills catch a lot of rain in August and September and the island half-closes.
• North (Chiang Mai, Chiang Rai, Pai, Mae Hong Son, Nan): the only part of Thailand with a real cool season. December and January nights drop to 13-16°C (55-61°F) in the valleys and near freezing on Doi Ang Khang and Doi Inthanon, so the morning mist, strawberry fields and camping crowds you see online are all a cool-season thing. The rains arrive in May and the hills are at their greenest from July to October.
• Isaan (Khon Kaen, Ubon Ratchathani, Nong Khai): hot and dry from November to April, and the hottest region of all in March and April, when 40°C (104°F) is normal. Rains run May to October and are lighter than on the coasts.

Two things people get wrong. First, the hot season from March to May is fine for beaches as long as you are on the coast: sea breezes take the edge off 36°C (97°F) and the Andaman water is at its clearest. It is the inland cities and the ruins that become hard work. Second, the rainy season is not a write-off. Most days bring two or three hours of heavy rain in the late afternoon and a dry morning, and the countryside around Chiang Mai and the waterfalls in Kanchanaburi are at their best. The exceptions are September and October in Bangkok, when flooding streets are routine, and the same months on the Andaman coast, when swimming is dangerous and ferries get cancelled.

Prices in Thailand move more with the calendar than almost anywhere in Asia, and the swings are bigger on the islands than in the cities.

• Peak (20 December to 10 January): resorts on Phi Phi, Ko Lanta and Samui charge double or triple their low-season rate, add compulsory gala dinners on 24 and 31 December and impose minimum stays of three to five nights. Flights from Europe and the sleeper trains to Chiang Mai sell out weeks ahead. Book this period by September.
• High (November to February, outside the peak weeks): full prices and busy sights, but Thailand is big and only Phi Phi, Patong and the Grand Palace feel genuinely overrun. Chinese New Year (6 February 2027) brings a second surge of regional visitors to Bangkok, Phuket and Chiang Mai for about a week.
• Shoulder (March to May and late October): rates drop 20-30% from mid-March as the heat builds, except around Songkran when domestic travel peaks and trains and buses out of Bangkok fill. Late October and early November on the Andaman coast is the sweet spot: the sea has settled, the hotels are still on low-season rates and the Europeans have not arrived.
• Low (June to early October): 30-50% discounts, walk-in rates on the islands and quiet temples. Some small resorts on Ko Lanta, Ko Chang and Khao Lak close entirely from June to September, so check that the place you want is open.

A concrete example: a mid-range beachfront room on Ko Lanta that costs 3,500 THB (about $105) in January is often 1,500-1,800 THB in September, and the same gap applies to private longtail charters and dive courses.

Buddhist holidays follow the lunar calendar and move each year; fixed dates are given where they exist. On Buddhist holy days alcohol sales are banned nationwide for the day, bars close and 7-Elevens cover the beer fridges, so plan around Makha Bucha, Visakha Bucha, Asalha Bucha and the start and end of Buddhist Lent. Check dates with the Tourism Authority of Thailand before you build a trip around one.

• January: New Year’s Day (1 January, public holiday). Bo Sang Umbrella Festival in the craft village of Bo Sang outside Chiang Mai, third weekend of the month, with a parade of hand-painted parasols.
• February: Chinese New Year (6 February 2027) fills Bangkok’s Chinatown with lion dances and firecrackers along Yaowarat Road. Chiang Mai Flower Festival, first weekend of February, parades through the Old City and fills Suan Buak Haad park with displays. Makha Bucha falls on the February or March full moon.
• March: National Muay Thai Day on 17 March brings a mass wai khru ceremony to the ruins of Ayutthaya. Hot and hazy in the north; a quiet month elsewhere.
• April: Chakri Day (6 April). Poy Sang Long in Mae Hong Son in early April, when Shan boys are paraded in princely costume before ordaining as novices. Songkran, 13 to 15 April, is Thai New Year and a three-day national water fight; Chiang Mai’s moat road and Bangkok’s Silom Road and Khao San Road are the epicentres, and Chiang Mai keeps going for the better part of a week. Banks and offices close, long-distance transport is packed and road deaths spike, so avoid driving.
• May: Labour Day (1 May) and Coronation Day (4 May). The Royal Ploughing Ceremony at Sanam Luang in Bangkok opens the rice-planting season in early May. Visakha Bucha, the most important Buddhist day, falls on the May full moon with candlelit processions at every temple; Nakhon Pathom’s Phra Pathom Chedi is the classic place to see it. The Rocket Festival (Bun Bang Fai) in Yasothon, second weekend of May, fires home-made rockets at the clouds to call the rain.
• June: Phi Ta Khon, the ghost mask festival in Dan Sai, Loei province, over three days in late June or early July (the exact dates are set by village mediums each year). The quietest month for international visitors.
• July: Asalha Bucha and Khao Phansa, the start of Buddhist Lent, on the July full moon. Ubon Ratchathani’s Candle Festival parades enormous carved wax sculptures through the city that weekend. The King’s birthday (28 July) is a public holiday.
• August: The Queen Mother’s birthday and Mother’s Day (12 August). Otherwise the low season at its lowest, with rain on the Andaman side and good weather on the Gulf.
• September to October: Phuket’s Vegetarian Festival runs for nine days from the start of the ninth Chinese lunar month, usually late September or October, with street processions in Phuket Town in which entranced devotees pierce their cheeks. Ok Phansa, the end of Lent on the October full moon, brings the Naga Fireball night on the Mekong at Nong Khai, illuminated boat processions at Nakhon Phanom and the buffalo races in Chonburi. Chulalongkorn Day (23 October).
• November: Loy Krathong on the November full moon (24 November 2026; expected around 14 November 2027). Thais float candlelit baskets on every river and pond; Sukhothai’s historical park stages a five-night light-and-sound version, and Chiang Mai’s Yi Peng lantern release happens the same nights along the Ping River and at Tha Phae Gate, with ticketed mass releases outside the city costing several thousand baht. The Surin Elephant Round-up in Surin is the third weekend of November and the Monkey Buffet in Lopburi the last Sunday.
• December: King Bhumibol Memorial Day and Father’s Day (5 December), Constitution Day (10 December). Wonderfruit, a four-day music and arts festival near Pattaya, runs in mid-December. New Year’s Eve countdowns and fireworks along the Chao Phraya at ICONSIAM and CentralWorld in Bangkok mark the start of peak season.

Thailand is hot in every month, so the question is how much rain gear and how many warm layers to add.

• Every season: lightweight, quick-dry clothes; a sarong or light trousers and a top that covers your shoulders for temples; sandals that slip off easily (you will remove shoes dozens of times a day); 50+ sunscreen and a hat; DEET or picaridin repellent, since dengue is present year-round; a refillable bottle, because tap water is not drinkable and every 7-Eleven sells refills.
• Cool season (November to February): a fleece or light jacket for the north, where evenings in Chiang Mai and Pai drop to 14°C (57°F) and the summit of Doi Inthanon can hit 5°C (41°F) before dawn. A proper warm layer if you plan to camp on Doi Ang Khang or hike Phu Kradueng.
• Hot season (March to May): the thinnest clothes you own, electrolyte sachets, and a plan to do temples and ruins before 10am. A KN95 mask if you will be in the north during burning season. For Songkran, a dry bag for your phone and clothes you do not mind soaking.
• Rainy season (June to October): a compact umbrella beats a rain jacket in 30°C (86°F) humidity; sandals or shoes that can get wet; a dry bag for boat trips; and anti-mould bags for electronics if you are on the islands for more than a week. Leave the hairdryer behind: nothing dries anyway.