Is the air in Chiang Mai safe today?

For most people, yes. Right now the US AQI in Chiang Mai is 90, which counts as moderate. Acceptable. Unusually sensitive people should ease off long, intense outdoor effort.

When is the best time to be outside in Chiang Mai?

Sat 10:00–13:00. That is the cleanest stretch in the next 24 hours, with the US AQI averaging about 52. The worst hour is around Sat 23:00, at 98.

What is the main pollutant in Chiang Mai?

Fine particles (PM2.5). It drives the index right now, at 30 µg/m³. Tiny particles from combustion, fires and dust that reach deep into the lungs. The main driver of AQI worldwide.

How does Chiang Mai's air compare with the WHO guideline?

1.2 times the guideline. Over the next 24 hours PM2.5 averages about 18 µg/m³, against the World Health Organization's 24-hour guideline of 15 µg/m³. NO2 and O3 are also forecast above their guideline levels.

How many cigarettes is a day of Chiang Mai's air?

About 0.8 cigarettes. Over the next 24 hours PM2.5 averages about 18 µg/m³. By Berkeley Earth's rule of thumb, 22 µg/m³ breathed for a day is roughly one cigarette.

Will air quality in Chiang Mai improve this week?

Tuesday looks cleanest. Its AQI peaks at 97, against 133 on Sunday, the worst day in the forecast.

Chiang Mai air quality

Thailand · Live AQI and hourly forecast for the next 5 days · valid Sat 00:00 local time

Moderate

US AQI, mostly PM_2.5

Model estimate. Nearby measurements are shown separately.

Acceptable. Unusually sensitive people should ease off long, intense outdoor effort.

Next 24 hours: 46–98US AQI, highest around Sat 23:00
Best time outside: Sat 10:00–13:00US AQI about 52
PM_2.5 vs WHO guideline: 1.2×18 µg/m³ over 24 h, guideline 15
Cigarette equivalent: ≈ 0.8 a dayBerkeley Earth rule of thumb

Loading the live globe…

The live globe, centred on Chiang Mai. Switch pollutants, drag through the next 5 days or press play. Full map →

Pollutants in Chiang Mai right now

Pollutant	Now	Level	Next 24 h vs WHO
Fine particles PM_2.5	30 µg/m³	Moderate	1.2×
Coarse particles PM₁₀	31 µg/m³	Good	0.4×
Nitrogen dioxide NO₂	42 µg/m³	Good	1.2×
Ozone O₃	10 µg/m³	Good	1.1×
Sulphur dioxide SO₂	17 µg/m³	Good	0.2×
Carbon monoxide CO	2,328 µg/m³	Good	0.4×
Aerosol optical depth	0.12	Whole atmosphere · dimensionless
Desert dust	0 µg/m³	Modelled surface dust
UV index	0	Low

“Next 24 h vs WHO” compares the forecast with the World Health Organization’s 2021 guideline levels: 24-hour means of 15 µg/m³ for PM_2.5, 45 for PM₁₀, 25 for NO₂, 40 for SO₂ and 4 mg/m³ for CO, and 100 µg/m³ over 8 hours for ozone. Above 1× is above the guideline. Levels follow the US AQI, which is far less strict than the WHO, so air rated Good can still be above a guideline.

Next 48 hours

Hourly US AQI. Highest 133 around Sun 14:00, lowest 46 around Sat 11:00.

50100

Good 0–50Moderate 51–100Sensitive 101–150Unhealthy 151–200Very unhealthy 201–300Hazardous 301+

5-day air quality forecast for Chiang Mai

Daily range of the hourly US AQI, from lowest to highest, on a scale of 0 to 150.

Day	US AQI	At worst	Worst hour	PM_2.5 avg	UV max
Sat 14 Nov	46–98	Moderate	23:00	18	7 High
Sun 15 Nov	63–133	Sensitive	14:00	25	7 High
Mon 16 Nov	64–119	Sensitive	15:00	21	7 High
Tue 17 Nov	46–97	Moderate	13:00	17	7 High

Common questions about the air in Chiang Mai

Is the air in Chiang Mai safe today?
For most people, yes. Right now the US AQI in Chiang Mai is 90, which counts as moderate. Acceptable. Unusually sensitive people should ease off long, intense outdoor effort.
When is the best time to be outside in Chiang Mai?
Sat 10:00–13:00. That is the cleanest stretch in the next 24 hours, with the US AQI averaging about 52. The worst hour is around Sat 23:00, at 98.
What is the main pollutant in Chiang Mai?
Fine particles (PM_2.5). It drives the index right now, at 30 µg/m³. Tiny particles from combustion, fires and dust that reach deep into the lungs. The main driver of AQI worldwide.
How does Chiang Mai's air compare with the WHO guideline?
1.2 times the guideline. Over the next 24 hours PM_2.5 averages about 18 µg/m³, against the World Health Organization's 24-hour guideline of 15 µg/m³. NO₂ and O₃ are also forecast above their guideline levels.
How many cigarettes is a day of Chiang Mai's air?
About 0.8 cigarettes. Over the next 24 hours PM_2.5 averages about 18 µg/m³. By Berkeley Earth's rule of thumb, 22 µg/m³ breathed for a day is roughly one cigarette.
Will air quality in Chiang Mai improve this week?
Tuesday looks cleanest. Its AQI peaks at 97, against 133 on Sunday, the worst day in the forecast.

Measured near Chiang Mai

Station and measurements	Distance	US AQI	Level
Yupparaj Wittayalai School OpenAQ, reference monitor PM_2.5: 9.0 µg/m³ · Sat 00:00	0.6 km	50	Good
Unnamed sensor OpenAQ, low-cost sensor PM_2.5: 16 µg/m³ · Sat 00:00	1.1 km	64	Moderate
Unnamed sensor OpenAQ, low-cost sensor PM_2.5: 3.7 µg/m³ · Sat 00:00	2.6 km	21	Good

Air quality near Chiang Mai

US AQI right now. Cleanest nearby: Phnom Penh (53); worst: Kolkata (210). The tick on each bar is Chiang Mai, at 90.

Yangon 368 km SW 91 Moderate
Bangkok 582 km S 76 Moderate
Hanoi 758 km E 207 Very unhealthy
Phnom Penh 1,026 km SE 53 Moderate
Dhaka 1,049 km NW 158 Unhealthy
Kolkata 1,182 km NW 210 Very unhealthy

All 162 cities →

About this forecast

Forecast from CAMS global via Open-Meteo: the Copernicus Atmosphere Monitoring Service (CAMS) model at about 40 km resolution (about 10 km inside Europe). Global runs update every 12 hours and European runs every 24 hours. Models smooth out street-level peaks, so busy roads and industrial sites can be worse than shown. Nearby station measurements are independent observations, not adjustments to the forecast. The point forecast uses Open-Meteo’s CAMS products, including a separate carbon monoxide product; it can differ from the globe’s global grid. The AQI rates each hour on the US EPA scale, the same way the map colors it; official daily figures average over 24 hours (8 for ozone), so they can read lower after a short peak. Readings for 18.79°N, 98.99°E, valid 2026-11-13 17:00 UTC.