Thailand in July means rain on most of the country but dry spells on Koh Samui and the Gulf islands, at low-season prices. Thailand in October is a turning point: the rain eases in Bangkok and the north, the Andaman marine parks reopen and the Gulf turns wet. Below, every month has the same short guide: weather by region, where to go, where not to, the festivals of 2026 and 2027, park closures and prices. Dates checked on 14 November 2026.
Thailand month by month: the year in short
Three seasons shape the year. The cool, dry season runs from mid-October to mid-February, the hot season from mid-February to mid-May and the rainy season from mid-May to mid-October. The Gulf of Thailand works the other way round, with its rain from October to December.
The weather lines for each month use the same 1991 to 2020 averages of the Thai Meteorological Department as our guide to the best time to visit Thailand, which puts all twelve months in one table. We use four stations: Bangkok, Chiang Mai for the north, Phuket for the Andaman coast and Koh Samui for the Gulf. A rain day here is a day with at least 1 mm.
Thailand in January
January is one of the best months of the year: dry and sunny almost everywhere, with cool nights in the north. It is also the busiest and the most expensive.
- Bangkok: 33°C (91°F) by day, 23°C (74°F) at night, 24 mm of rain on about 2 days.
- North, Chiang Mai: 30°C (86°F), 16°C (60°F), 11 mm on 1 day.
- Andaman coast, Phuket: 33°C (91°F), 25°C (77°F), 50 mm on 4 days.
- Gulf, Koh Samui: 29°C (84°F), 24°C (76°F), 127 mm on 8 days.
Where to go. Anywhere. The sea on the Andaman side is at its calmest, so it is the month for Phuket, Krabi, the Similan Islands and Koh Lipe. In the north, mornings on Doi Inthanon are cold enough for a fleece and the Kew Mae Pan trail is open.
Where to avoid. Nowhere really. Koh Samui still gets showers in early January, and in Chiang Mai the first smoke from farm fires can appear at the end of the month.
Festivals in January 2027. New Year's Day on 1 January gives a long weekend from 1 to 3 January. The Bo Sang Umbrella Festival, in the umbrella-making village about 9 km east of Chiang Mai, usually takes the third weekend of January and is expected from 15 to 17 January 2027. It is free.
Park closures. None of the big ones. All the marine parks on both coasts are open.
Prices and crowds. Peak season. January 2025 was the busiest month of that year, with about 3.7 million foreign arrivals reported. Book flights to Thailand, island hotels and night trains early.
Thailand in February
February is the driest month on the Andaman coast and in Bangkok, and the start of the best stretch on the Gulf islands. The north turns hazy towards the end of the month.
- Bangkok: 34°C (93°F) by day, 25°C (77°F) at night, 21 mm of rain on about 2 days.
- North, Chiang Mai: 33°C (91°F), 17°C (62°F), 10 mm on 1 day.
- Andaman coast, Phuket: 34°C (93°F), 25°C (78°F), 24 mm on 2 days.
- Gulf, Koh Samui: 29°C (85°F), 25°C (77°F), 64 mm on 4 days.
Where to go. Both coasts. February to April is the driest time on Koh Samui, Koh Phangan and Koh Tao. In Khao Sok, the giant Rafflesia flower blooms around February.
Where to avoid. The north in the last days of the month if you have asthma or travel with small children, as the smoke season starts.
Festivals in February 2027. Chinese New Year falls on 6 February 2027 and fills Yaowarat, the Chinatown of Bangkok, with lion dances and food stalls. The Chiang Mai Flower Festival reaches its 50th edition and is expected from 5 to 7 February 2027 in Nong Buak Haad Park, with the parade of flower floats on the Saturday. The city confirms the dates in January.
Makha Bucha falls on Sunday 21 February 2027, with the bank holiday on Monday 22. In the evening, people walk three times around their temple with candles and flowers.
Park closures. None.
Prices and crowds. Still high season, with the same rates as January.
Thailand in March
March is hot and dry, a good month for the beaches on both coasts and a bad one for the north, where the smoke peaks.
- Bangkok: 35°C (94°F) by day, 26°C (80°F) at night, 51 mm of rain on about 3 days.
- North, Chiang Mai: 35°C (96°F), 20°C (68°F), 20 mm on 2 days.
- Andaman coast, Phuket: 34°C (94°F), 26°C (79°F), 81 mm on 6 days.
- Gulf, Koh Samui: 30°C (87°F), 25°C (78°F), 116 mm on 5 days.
Where to go. The islands. The Similans and Koh Lipe still have clear water, and the Gulf islands are dry. Our ranking of the best islands in Thailand gives the season of each one.
Where to avoid. Chiang Mai, Chiang Rai and Pai. On 29 March 2026, Chiang Mai topped the IQAir world ranking with an air quality index of 263, a level classed as very unhealthy.
Festivals in March 2027. No national holiday and no major festival. It is a quiet month.
Park closures. None.
Prices and crowds. The beaches stay in high season. In the north, the smoke keeps many visitors away.
Thailand in April
April is the hottest month of the year, and Songkran, from 13 to 15 April, makes it the liveliest.
- Bangkok: 36°C (96°F) by day, 27°C (81°F) at night, 93 mm of rain on about 5 days.
- North, Chiang Mai: 37°C (98°F), 23°C (74°F), 54 mm on 5 days.
- Andaman coast, Phuket: 34°C (94°F), 26°C (79°F), 135 mm on 10 days.
- Gulf, Koh Samui: 32°C (89°F), 26°C (79°F), 83 mm on 6 days.
Where to go. The Gulf islands, at the end of their driest stretch. Any town for Songkran, with Silom Road in Bangkok and the moat of Chiang Mai's old city the busiest spots.
Where to avoid. The north until the rain clears the smoke at the end of the month, and long afternoons outdoors in Bangkok.
Festivals in April 2027. Chakri Day on Tuesday 6 April, then Songkran 2027 from Tuesday 13 to Thursday 15 April, the Thai New Year and a nationwide water fight. Banks and government offices, immigration included, close for the three days. Pattaya holds its own water days later, on 18 and 19 April in 2026.
Park closures. None, but plan visa errands around the Songkran days.
Prices and crowds. Trains and buses are full around Songkran as Thais travel home. In 2026, hotels in Chiang Mai expected 50 to 60% occupancy for Songkran, against 80 to 90% in a normal year, because of the haze.
Thailand in May
May is when the rainy season starts, on 15 May in 2026: cheaper, greener and still sunny most mornings, with the Gulf islands as the best beach choice.
- Bangkok: 35°C (95°F) by day, 27°C (80°F) at night, 217 mm of rain on about 12 days.
- North, Chiang Mai: 35°C (94°F), 24°C (76°F), 168 mm on 12 days.
- Andaman coast, Phuket: 33°C (92°F), 26°C (79°F), 237 mm on 16 days.
- Gulf, Koh Samui: 33°C (91°F), 26°C (78°F), 132 mm on 11 days.
Where to go. Koh Samui, Koh Phangan, where the Full Moon Party still runs every month, and Koh Tao. Bangkok at low prices. The Similan Islands until 15 May.
Where to avoid. Swimming on Andaman beaches with red flags. On 15 May 2026, the first day of the season, a man was swept away at Nai Thon beach on Phuket in waves over 2 metres.
Festivals in May 2027. Coronation Day on Tuesday 4 May gives banks a four-day weekend from 1 to 4 May. Visakha Bucha, the day of the Buddha's birth, enlightenment and death, falls on Thursday 20 May. In Yasothon, in the north-east, the Rocket Festival fires home-made bamboo and PVC rockets into the sky. It ran from 8 to 10 May in 2026 at Phaya Thaen Park, and the 2027 dates are expected in mid-May.
Park closures. The Similan Islands close on 16 May, and so do most of the small islands of Mu Koh Lanta park. The speedboats between Koh Lanta and Koh Lipe stop around 20 May. In Khao Sok, the Rafflesia area near km 111 is closed from 1 May to 31 October.
Prices and crowds. Low season starts. About 2.27 million foreign visitors came in May 2025, against 3.7 million in January, and hotels on Phuket and Krabi cut their rates.
Thailand in June
June is low season with afternoon storms: go to the Gulf islands, and see Bangkok and the north at low prices.
- Bangkok: 34°C (93°F) by day, 26°C (80°F) at night, 198 mm of rain on about 13 days.
- North, Chiang Mai: 33°C (92°F), 24°C (76°F), 118 mm on 12 days.
- Andaman coast, Phuket: 33°C (91°F), 26°C (78°F), 249 mm on 16 days.
- Gulf, Koh Samui: 33°C (91°F), 25°C (78°F), 134 mm on 10 days.
Where to go. The Gulf islands. Chiang Mai, where June is drier than May or August. Khao Sok, green again after the dry months.
Where to avoid. Speedboat trips on the Andaman side on rough days, and the far islands of Koh Chang, whose speedboats stopped from 1 June to 30 September in 2026.
Festivals in June 2027. Queen Suthida's birthday on Thursday 3 June is a public holiday. In Dan Sai, in Loei province, Phi Ta Khon brings out men in tall masks and patchwork costumes for three days of processions. It ran from 20 to 22 June in 2026. There is no fixed date: a spirit medium chooses it each year, so the 2027 festival may fall in June or July.
Park closures. Koh Rok, from Koh Lanta, closes on 1 June until 30 September. Nam Talu cave in Khao Sok closes from 1 June to 30 November, and it floods within minutes after rain.
Prices and crowds. One of the cheapest months, with May and September.
Thailand in July
July is rainy but workable: short storms, low prices, and the Gulf islands are the best beach choice. It is a good month for a first trip if you skip the Andaman beaches.
- Bangkok: 34°C (92°F) by day, 26°C (79°F) at night, 190 mm of rain on about 14 days.
- North, Chiang Mai: 32°C (90°F), 24°C (76°F), 149 mm on 14 days.
- Andaman coast, Phuket: 32°C (90°F), 26°C (78°F), 240 mm on 16 days.
- Gulf, Koh Samui: 32°C (90°F), 25°C (77°F), 117 mm on 11 days.
Where to go. Koh Samui, Koh Phangan and Koh Tao, with half the rain of Phuket. Chiang Mai and the rice fields of the north, green from about July. Bangkok, with temples in the morning and malls when the storm comes.
Where to avoid. Andaman beaches for swimming. In July 2026, two British tourists had to be rescued at Nai Thon on Phuket after swimming past the red flags. Phuket is still fine for the Old Town, Phi Phi and Phang Nga Bay on calm days. Koh Chang has its wettest months from July to September.
Festivals in July 2027. Asalha Bucha falls on Sunday 18 July, with the holiday on Monday 19, and Buddhist Lent starts the next day. Ubon Ratchathani celebrates with its Candle Festival, a parade of giant wax sculptures. It ran from 28 to 30 July in 2026 on Thung Si Mueang, and should follow the holy days of 18 and 19 July in 2027. The King's Birthday on Wednesday 28 July is a public holiday.
Park closures. Koh Rok, Nam Talu, the Similans and the small islands of Mu Koh Lanta stay closed. Maya Bay is open until 31 July.
Prices and crowds. Low season on the Andaman coast, with hotels at their low-season rates. Our guide to the Thailand rainy season explains what a wet day looks like and how to keep a trip flexible.
Thailand in August
August is wet in the north and on the Andaman coast, but it is the driest month of the rainy season on Koh Samui.
- Bangkok: 33°C (92°F) by day, 26°C (79°F) at night, 227 mm of rain on about 16 days.
- North, Chiang Mai: 32°C (89°F), 24°C (75°F), 223 mm on 17 days, its wettest month.
- Andaman coast, Phuket: 32°C (90°F), 26°C (78°F), 309 mm on 17 days.
- Gulf, Koh Samui: 32°C (90°F), 25°C (77°F), 102 mm on 10 days.
Where to go. The Gulf islands. Waterfalls are full, so Doi Inthanon near Chiang Mai is worth a day if the road is clear.
Where to avoid. Maya Bay, closed from 1 August. Long treks in the north, where trails are muddy and leeches are out.
Festivals in August 2027. Thursday 12 August is the birthday of Queen Sirikit, the Queen Mother, and Mother's Day. The cabinet confirmed in July 2026 that it stays a yearly public holiday.
Park closures. Maya Bay on Koh Phi Phi Leh from 1 August to 30 September, plus Koh Rok, Nam Talu, the Similans and the small islands of Mu Koh Lanta.
Prices and crowds. Low season, with the same rates as July.
Thailand in September
September is the wettest month in Bangkok and on Phuket, and the cheapest time of the year. The Gulf islands remain the safe beach bet.
- Bangkok: 33°C (92°F) by day, 25°C (78°F) at night, 336 mm of rain on about 18 days.
- North, Chiang Mai: 32°C (90°F), 24°C (75°F), 207 mm on 15 days.
- Andaman coast, Phuket: 32°C (89°F), 25°C (77°F), 350 mm on 19 days.
- Gulf, Koh Samui: 32°C (89°F), 25°C (77°F), 118 mm on 11 days.
Where to go. Koh Samui, Koh Phangan and Koh Tao. In Bangkok, plan museums, markets and a cooking class for the afternoons.
Where to avoid. A beach trip to Phuket, Krabi or Koh Lanta: Phuket gets only 108 hours of sunshine in September, against 279 in January. Heavy rain can flood Bangkok, as it did from 24 to 27 September 2026, when the city declared a disaster in all 50 districts.
Festivals in September 2027. No national holiday. The Phuket Vegetarian Festival is expected to start on 30 September 2027, with the lantern poles raised the evening before.
Park closures. Maya Bay and Koh Rok until 30 September, the Similans and Nam Talu as before.
Prices and crowds. The quietest month, with the lowest hotel rates on the Andaman coast.
Thailand in October
October is a month of change: Bangkok and the north dry out towards the end, the Andaman coast stays wet but reopens its marine parks, and the Gulf islands turn rainy from mid-month.
- Bangkok: 33°C (92°F) by day, 25°C (77°F) at night, 289 mm of rain on about 14 days.
- North, Chiang Mai: 32°C (89°F), 23°C (73°F), 124 mm on 9 days.
- Andaman coast, Phuket: 32°C (89°F), 25°C (77°F), 336 mm on 19 days.
- Gulf, Koh Samui: 31°C (87°F), 24°C (76°F), 295 mm on 16 days.
Where to go. Chiang Mai and the north in the second half of the month, before the high-season prices. Phuket Town for the Vegetarian Festival. The Similan Islands from 15 October, when the season opens.
Where to avoid. Koh Samui, Koh Phangan and Koh Tao from mid-October. A pure beach holiday on the Andaman coast in the first half of the month.
Festivals in October. The Phuket Vegetarian Festival ran from 10 to 18 October 2026 in Phuket Town, with processions from the Chinese shrines and piercing rituals. In 2027 it is expected from 30 September to 8 October.
Ok Phansa, the end of Buddhist Lent, fell on 26 October in 2026 and should fall around 15 October in 2027, the full moon. That night, crowds watch for the Naga fireballs over the Mekong in Nong Khai, and Nakhon Phanom floats illuminated boats. The 13th is a memorial day for King Bhumibol, and Chulalongkorn Day on 23 October has its holiday on Monday 25 October in 2027.
Park closures. Reopenings, mostly. Koh Rok opens on 1 October, the Similans and the islands of Mu Koh Lanta on 15 October, and the speedboats to Koh Lipe start again the same day. The Kew Mae Pan trail on Doi Inthanon stays shut until November.
Prices and crowds. Still low-season rates for most of the month, which makes late October a good deal in the north.
Thailand in November
November opens the high season in Bangkok and the north, with Loy Krathong, but it is the wettest month on Koh Samui. The cool season was declared on 9 November in 2026.
- Bangkok: 33°C (92°F) by day, 25°C (76°F) at night, 45 mm of rain on about 4 days.
- North, Chiang Mai: 31°C (87°F), 20°C (68°F), 41 mm on 3 days.
- Andaman coast, Phuket: 32°C (90°F), 25°C (77°F), 178 mm on 13 days.
- Gulf, Koh Samui: 30°C (85°F), 24°C (75°F), 445 mm on 16 days.
Where to go. Bangkok, Chiang Mai and Sukhothai for the festival. The Andaman coast in the second half of the month, as the rain eases.
Where to avoid. Koh Samui, Koh Phangan and Koh Tao. The far south can still flood: in November 2025, Hat Yai received about 630 mm of rain in three days. From 9 to 13 November 2026, the weather department again warned of heavy rain and waves over 2 metres in the south.
Festivals in November 2026. Loy Krathong falls on 24 November, when people float small baskets of banana leaves and candles on rivers and ponds. In Chiang Mai the same nights are Yi Peng, with the ticketed lantern release of the CAD Khomloi festival on 24 and 25 November at Mae On, from about 4,900 THB.
Sukhothai Historical Park holds its events from 15 to 24 November. The Surin Elephant Round-up runs from 14 to 25 November, with the main shows reported for 21 and 22 November. Pattaya's free International Fireworks Festival lights up the beach on 27 and 28 November. In 2027, Loy Krathong is expected on 14 November.
Park closures. Ang Thong Marine Park, the day trip from Koh Samui, closes from 1 November to about 15 December. The Kew Mae Pan trail reopens.
Prices and crowds. High season starts, and the cheaper Yi Peng tickets sell out early. The Andaman coast costs less in late November than over Christmas.
Thailand in December
December is peak season: dry and pleasant in Bangkok and the north, calm on the Andaman coast, and the most expensive around Christmas and New Year.
- Bangkok: 32°C (90°F) by day, 23°C (74°F) at night, 12 mm of rain on about 1 day.
- North, Chiang Mai: 29°C (85°F), 17°C (62°F), 14 mm on 1 day.
- Andaman coast, Phuket: 32°C (90°F), 25°C (77°F), 82 mm on 8 days.
- Gulf, Koh Samui: 29°C (85°F), 24°C (75°F), 263 mm on 12 days.
Where to go. Bangkok, the north and the whole Andaman coast, from Phuket and Krabi to Koh Lipe.
Where to avoid. The Gulf islands in the first half of the month, and last-minute bookings around Christmas.
Festivals in December 2026. Wonderfruit, the arts and music festival, runs from 3 to 7 December at The Fields, Siam Country Club, near Pattaya. Father's Day on 5 December and Constitution Day on 10 December are public holidays. On 31 December, fireworks go up along the Chao Phraya in Bangkok for the countdown.
In 2027 the 5 December holiday moves to Monday 6 December, and New Year's Eve on a Friday opens a long weekend to 2 January 2028.
Park closures. Ang Thong reopens around 15 December. Nam Talu cave in Khao Sok reopens in December, on 1 December, or on 14 December according to some sources.
Prices and crowds. The highest of the year. Island rooms can cost twice the low-season rate over Christmas and New Year, and night trains to Chiang Mai sell out.
Thailand in July or August, October or November: which to choose
July or August? Close to the same. August is wetter in the north and in Bangkok, but drier on Koh Samui, and Maya Bay is closed. With a free choice, July is a little easier for a trip that mixes Bangkok, Chiang Mai and the Gulf.
October or November? November, unless you want low prices or the Vegetarian Festival. November brings dry weather to Bangkok and the north, Loy Krathong and a drying Andaman coast. October is cheaper, but wet on both coasts by the end. Avoid the Gulf islands in both.
Whatever the month, a two-week route through Bangkok, the north and one coast works, as long as you switch the coast with the season. Our Thailand itineraries give day-by-day plans, and the Thailand travel guide covers visas, money and transport before you go.