Burning Season in Chiang Mai: Dates, Numbers, and the Clean-Air Playbook

Every year, roughly from late January to mid-April, agricultural burning across the upper Mekong region meets a bowl-shaped valley and a temperature inversion, and Chiang Mai's famously soft air turns hazy. March is usually the peak. By Songkran (mid-April) the rains start rinsing it out, and from May to January the air here is soft mountain air again.

That's the whole calendar. Everything else is numbers and playbook — both below, both live.

Today's number

Chiang Mai air right now: PM2.5 9.6 µg/m³ — Very good (US AQI 50). Observed 2026-08-17 07:00. Modelled by CAMS via Open-Meteo — a city-scale model, not a street sensor; treat it as the weather report, not a diagnosis.

The last seven observed days, same model, generated 2026-08-17.

Two scales float around town: US AQI (the colored 0–500 number) and micrograms of PM2.5 per cubic meter, which is what Thailand's Pollution Control Department bands run on. This page reports µg/m³ first because that's what the Thai advisories, school closure decisions, and your purifier's display all speak.

The playbook, in the order locals actually do it

1. Watch the number, not the sky. Haze photographs worse than it measures some days and better on others. The strip above updates itself; motdang.net keeps the live city dashboard with the same feed. 2. Masks: N95 or nothing. A fitted N95 (หน้ากาก N95, nâa-gàak — mask) filters PM2.5; a surgical mask mostly filters your conscience. Pharmacies stock them everywhere — here's the pharmacy map. 3. One sealed room with a HEPA purifier. You don't need to filter the whole house — you need one bedroom where the number is boring. Local supermarkets and Lazada carry HEPA units from about ฿2,500 (indicative, August 2026); filters are the recurring cost. 4. Time your outdoor life. Early evenings after wind shifts are often the day's best window; mid-morning inversions are often the worst. Check, then run. 5. Know your exit. The south — the gulf islands, Phuket, anywhere with sea wind — runs clean while the North burns. Long-stayers routinely book February–April elsewhere and come home for the rains with the DTV's multi-entry runway.

If you're here for medical care

Timing matters more than most itineraries admit:

• Respiratory anything — asthma, COPD, post-COVID lungs — schedule consultations and recovery windows May through January if you can. Your lungs and your follow-up appointments will both go smoother.
• Elective surgery with a long recovery — the recovery apartment's air quality is part of the surgical plan. Every concierge recovery briefing between January and April includes a purifier line item; that's not upsell, it's the checklist.
• Already here and struggling? The private hospitals on the hospital map all run walk-in clinics; smoke-season respiratory visits are the most routine thing they see all year.

Not medical advice — a logistics note. Breathing decisions belong to you and a physician.

Currency on this page: ฿100 ≈ $3.01 / €2.61 / £2.23 — Bank of Thailand mid rate, 2026-08-14. Live board runs on the household's own feed.

FAQ

When does burning season start and end in Chiang Mai?

Late January to mid-April, peaking in March, easing with the first real rains around Songkran. Outside that window the air is genuinely good — better than most Western cities' winters.

Is it safe to visit during burning season?

Millions of people live through it every year with masks, purifiers, and indoor plans. Whether you should — with your lungs, your kids, your marathon training — is a live question the daily number answers better than any blog post, this one included.

Do locals really leave?

Some do — March especially. The DTV and long-stay visas make the seasonal shuffle easy, and the destinations pages cover the clean-air escapes.

Planning treatment around the smoke calendar? The concierge desk sequences surgery, recovery, and the seasons in one plan — quote in writing before you fly. Questions cost nothing: tap to reveal the encrypted address

Reviewed 17 Aug 2026 by the Defiant team · every price is confirmed in writing before you book.