March is the month Thailand splits in two. The beaches are still in their dry season and close to perfect – Phuket at 32°C, the Gulf islands at their calmest – while the north disappears under smoke. Chiang Mai’s burning season peaks in March, and it is the single most important thing to know before booking a Thailand trip this month.
The burning season, stated honestly
From late February through April, agricultural and forest fires across northern Thailand and the neighbouring region fill the valleys with smoke. Chiang Mai sits in a bowl ringed by mountains, and temperature inversions trap the haze: the city has repeatedly topped global air-quality rankings during the season, with AQI readings in the 200s and PM2.5 many times World Health Organization guidance. Roughly 70 per cent of Chiang Mai’s fine particulate pollution in April comes from biomass burning.
Fire activity peaks in March and fades in May as the rains arrive. What that means practically:
- If you have asthma, COPD, a heart condition, are pregnant or are travelling with small children, do not plan a March trip to Chiang Mai, Chiang Rai, Pai or Mae Hong Son.
- If you go anyway, check IQAir or the Thai Pollution Control Department daily, bring properly fitted N95 or KN95 masks, and pick accommodation with air purifiers – many Chiang Mai hotels now advertise them.
- The viewpoints are the point of the north and in March you often cannot see them. Doi Suthep looks out over white nothing on a bad day.
None of this applies to the south. The islands and the Bangkok region are unaffected by the northern haze.
Weather: three different countries
Thailand does not have one climate, and March shows it clearly:
- Bangkok – about 33°C by day and 26°C at night, with only around 50 mm of rain over three days. Hot, dry, and getting hotter: March is the start of the Thai hot season.
- Phuket and the Andaman coast – about 32°C, with roughly 60 mm of rain. The dry-season tail; seas are calm, visibility is good, and the boats run.
- Chiang Mai and the north – about 34°C by day and 21°C at night with almost no rain. On paper the best weather of the year; in practice the smoke.
- Koh Samui, Koh Phangan and Koh Tao – the Gulf coast runs on a different monsoon from the Andaman, and its dry season covers roughly January to August. March is excellent there.
The Andaman islands are still open – until 15 May
The Similan and Surin Islands national parks close every year from 16 May to 14 October. It is a fixed annual closure set by Thailand’s Department of National Parks for ecosystem recovery, not a weather call, and it applies to every operator without exception.
March sits comfortably inside the open season, with the calmest seas and the best underwater visibility of the year. If the Similans are on your list, March and April are the months to do them, and liveaboards book up well ahead for exactly that reason.
What March is best for
Beaches and diving, essentially. The Andaman coast – Phuket, Krabi, Railay, Koh Lanta, Koh Phi Phi – is at the end of its best run, and the Gulf islands are in the middle of theirs. Bangkok is hot but entirely functional, and the temples and markets do not care what the thermometer says.
What March is not good for: the north, mountains, trekking and anything that depends on a view. Save those for November, December or January.
Prices and crowds
March is the tail of the high season. Rates on the islands stay firm through the month and begin easing towards the end, as the hot season sets in and European half-terms finish. It is busier than April and considerably busier than the green season from May.
See how much a trip to Thailand costs for realistic daily numbers.
Practical notes for March
- The heat is the real constraint in Bangkok. Temples open early; go at 08:00, take the middle of the day indoors, and use the river boats and the BTS rather than walking long distances.
- Temple dress codes are enforced at the Grand Palace, Wat Phra Kaew and Wat Pho regardless of temperature: covered shoulders and knees.
- Songkran is coming. If your trip runs into mid-April, read the April page before booking internal transport – 13 to 15 April changes everything.
The March 2027 calendar
- All month – burning season at its peak across northern Thailand.
- All month – Similan and Surin islands open; Andaman seas at their calmest.
- Through March – the Thai hot season begins; Bangkok climbs through 33°C and keeps going.
- Late March – island rates begin easing as high season winds down.
Read alongside
- Thailand in February – the last clean month in the north.
- Thailand in April – Songkran, and the hottest weeks of the year.
- Best time to visit Thailand – all twelve months compared.
- How much a trip to Thailand costs – the numbers.
- Best islands in Thailand – and which coast they are on.
- Chiang Mai travel guide – and when to go instead.
- What to pack for Thailand – the hot-season list.
Frequently asked
Is March a good time to visit Thailand?
For the beaches, yes – both coasts are in good shape and the Andaman seas are at their calmest. For the north, no: March is the peak of the burning season and Chiang Mai’s air quality can be among the worst in the world.
What is the burning season in Chiang Mai?
Agricultural and forest burning across northern Thailand and the surrounding region from late February to April, peaking in March and fading in May. Mountains and temperature inversions trap the smoke in the valley; about 70 per cent of Chiang Mai’s April PM2.5 comes from biomass burning.
Should I avoid Chiang Mai in March?
If you have any respiratory or cardiac condition, are pregnant or are travelling with young children, yes. Otherwise, go in with open eyes: check air quality daily, bring N95 masks, book accommodation with air purifiers, and accept that the viewpoints may be invisible.
How hot is Thailand in March?
Bangkok averages about 33°C by day and 26°C at night; Chiang Mai reaches 34°C; Phuket sits around 32°C. March is the start of the Thai hot season and April is hotter.
Are the Similan Islands open in March?
Yes. Similan and Surin close annually from 16 May to 14 October, so March is inside the open season and has the calmest seas and best visibility of the year. Liveaboards book up well ahead.
Which Thai islands are best in March?
Both coasts work. The Andaman side – Phuket, Krabi, Koh Lanta, Koh Phi Phi – is at the end of its dry season, and the Gulf islands, Koh Samui, Koh Phangan and Koh Tao, are in the middle of theirs because they run on a different monsoon.
Does it rain in Thailand in March?
Very little. Bangkok gets around 50 mm across three days and Chiang Mai almost nothing. Phuket sees about 60 mm, usually as short afternoon showers.
Is March expensive in Thailand?
It is the tail end of high season, so island rates hold firm through most of the month and start easing towards the end. It is dearer than April and much dearer than the green season from May.
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Written by
John Morrison is the founder and lead travel writer at Packzup. Over the past decade he has explored destinations across Africa, the Americas, Asia, Europe, the Middle East, and Oceania — always self-funded, never on a press trip.
