If Chiang Mai is on your list, you’ve probably already heard about the burning season. It’s the one thing that catches people off guard about this otherwise fantastic city, and honestly, it’s the one thing we locals dread every year. Here’s what you need to know.
TL:DR – Try to avoid visiting Chiang Mai in February and March. Crop burning across northern Thailand and neighboring countries causes serious air pollution. If you can time your trip for November through January or April onwards, you’ll have a much better experience.
See the 5-day air quality forecast →
Check current Chiang Mai AQI on aqicn.orgWhen Is Chiang Mai’s Burning Season?
What Months Are the Worst?
Burning season runs roughly from February through April. The worst of it is usually concentrated in late February and March, though some years it kicks off earlier and other years it drags into April. By Songkran (mid-April) it’s almost always cleared up.
Why Does Chiang Mai Have a Burning Season?
The short answer is farming. After harvest, farmers across northern Thailand and the surrounding countries burn their fields to clear them for the next planting season. It’s been done this way for centuries and it’s cheap and effective from their perspective. On top of that, forest fires in the mountains and smoke drifting in from Laos, Myanmar, and Cambodia add to the problem. Chiang Mai sits in a valley, so when there’s no wind or rain, all that smoke just sits there like a lid on a pot.
Is Burning Season Getting Worse?
The Thai government talks about it every year. There are initiatives to promote alternative farming practices, awareness campaigns, occasional burning bans. But honestly, it mostly amounts to talk. The fundamental problem is that even if Thailand cleaned up its act completely, smoke from Myanmar, Laos, and Cambodia would still drift across the border. Those countries are poorer, less politically stable, and not in a position to coordinate a regional response anytime soon. So for the foreseeable future, burning season is something we live with.
How Bad Is Chiang Mai’s Air Quality During Burning Season?
What Does the AQI Look Like?
Bad enough that it regularly gets picked up by international news outlets. On the worst days, the AQI (Air Quality Index) can hit 300, 400, even 700+. For context, anything above 100 is considered unhealthy. Above 300 is hazardous. Chiang Mai has, on multiple occasions, been ranked the most polluted city in the world during peak burning season.
Chiang Mai regularly scores 300+ AQI during burning season 🙁
When it’s really bad, you can’t see the mountains from a few kilometers away. The sky turns grey-white, everything smells like a campfire, and the sunsets are an eerie deep orange. It’s honestly a pretty surreal contrast to the rest of the year when Chiang Mai is one of the most beautiful places I’ve ever lived.
How Is the 2026 Burning Season So Far?
This year actually got off to a surprisingly late start. February and early March were largely clear: blue skies, visible mountains, AQI readings that would pass for a normal day in any major city. A lot of us were cautiously optimistic. Then, around March 1st, it hit. Within a few days the AQI jumped to around 200 and the mountains disappeared behind a thick grey haze. As of early March 2026, we’re deep in it. Whether this turns into a short, sharp season or drags on through April is anyone’s guess, but the pattern of “fine one day, hazardous the next” is typical. That’s what makes burning season so hard to plan around.
What Are the Health Effects of Burning Season?
If you’re generally healthy and you limit your time outdoors on bad days, sticking to places that have air purifiers, it’s manageable. But for people with respiratory issues, kids, or elderly folks, it can cause real problems. The most common complaint among us locals is this kind of stuffiness in your head, like you’re coming down with a cold but without the runny nose. Long-term residents like us worry about what years of this does to your lungs. And then there’s the mental health side of it too. Three months of grey skies and not being able to go outside properly does wear on you.
How to Deal With Burning Season
What Locals Do to Avoid the Worst Effects
Everyone we know has at least one air purifier at home. Masks come back out (we’ve still got plenty from COVID). A lot of people, us included, escape south for a few weeks if they can swing it, though that means paying double rent which is annoying. There’s also an app that tracks which businesses use air purifiers, which is handy for picking a gym or cafe on the bad days.
Can You Still Enjoy Chiang Mai During Burning Season?
Honestly, yes, with some adjustments. Plenty of people visit during February and March and still have a great time. The smog isn’t constant; you’ll get bad days and perfectly fine days mixed together. If you stay in accommodation with an air purifier, stick to indoor activities on the worst days, and keep an eye on the AQI readings, it’s manageable. The city is also noticeably quieter during this period, which means fewer crowds at temples, easier restaurant reservations, and lower prices on accommodation. It’s not ideal, but it’s not a write-off either.
Where to Go in Thailand Instead
If you’d rather skip it entirely, head south. The beaches in Krabi, the islands off Koh Samui, or even just Bangkok don’t have this problem. We usually escape to Koh Phangan or Phuket for the worst of it and come back once the rains clear everything out. Southern Thailand in March is gorgeous.
Which Month Is Best to Visit Chiang Mai?
Plan your visit for November through January if you want the best weather, or come in April once the smoke clears. April also brings Songkran, Thailand’s New Year water festival. When I say city-wide water fight, I mean city-wide. It’s such a fun experience and absolutely worth timing your trip around.
Songkran water festival is crazy fun and worth coming to Chiang Mai for.
Chiang Mai’s burning season is a real thing you need to plan around, but don’t let it scare you off the city entirely. Time your trip right and you’ll see why so many of us choose to live here year-round despite it. Come in April for Songkran and you’ll get clear skies, warm weather, and the biggest water fight of your life.
https://www.iqair.com/th-en/newsroom/thailand-2021-burning-season
