Worst air pollution San Miguel de Allende, today and tomorrow
Today (20 September): Air quality in San Miguel de Allende is very poor. AQI, PM2.5, and PM10 are very poor; PM1 is moderate; NO2, O3, SO2, CO, and HCHO are good. Pollution peaks around 1:00 PM (PM2.5: 100/100).
Tomorrow (21 September 2026): Air quality in San Miguel de Allende is very poor. PM1 decreases to fair; all other pollutants stay as today. Pollution peaks around 12:00 AM (PM10: 100/100). Airmine updates local air quality forecasts four times daily.
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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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San Miguel de Allende's air quality benefits from its exceptional Guanajuato Bajío highland position at 1,910 metres, with consistent central Mexican plateau breezes providing background ventilation. Vehicle traffic on surrounding roads and the colonial heritage tourism, arts, and services corridor contribute modest local sources, while the elevated plateau position aids dispersal and San Miguel de Allende generally maintains among Mexico's more moderately ventilated major UNESCO colonial highland heritage city environments throughout most of the year.
Today - 20 September | Pollution peaks at 13:00
AQI:
Very poor
100/100
PM2.5 (fine particles):
Very poor
100/100
PM10 (coarse particles):
Very poor
100/100
NO2 (nitrogen dioxide):
Good
1.3/100
O3 (ozone):
Good
17.2/100
SO2 (sulfur dioxide):
Good
0.4/100
CO (carbon monoxide):
Good
0.4/100
HCHO (formaldehyde):
Good
0.9/100
PM1 (ultrafine particles):
Moderate
42.5/100
Levels show the poorest local air quality during the day
Tomorrow - 21 September | Pollution peaks at 00:00
AQI:
Very poor
100/100
PM2.5 (fine particles):
Very poor
88.2/100
PM10 (coarse particles):
Very poor
100/100
NO2 (nitrogen dioxide):
Good
1.3/100
O3 (ozone):
Good
18.1/100
SO2 (sulfur dioxide):
Good
0.5/100
CO (carbon monoxide):
Good
0.4/100
HCHO (formaldehyde):
Good
1.0/100
PM1 (ultrafine particles):
Fair
31.8/100
Frequently Asked Questions
Is air quality bad in San Miguel de Allende right now?
On 20 September 2026, overall air quality in San Miguel de Allende is very poor. AQI is the main air quality indicator at 100/100. Pollution peaks around 1:00 PM (PM2.5: 100/100).
Will air quality be worse tomorrow in San Miguel de Allende?
On 21 September 2026, air quality conditions in San Miguel de Allende will be similar to today, with AQI forecast at very poor at 100/100. Pollution peaks around 12:00 AM (PM10: 100/100).
When is air pollution at its worst in San Miguel de Allende?
San Miguel de Allende usually sees its poorest air quality when traffic on the surrounding roads and seasonal tourism traffic coincide with periods when weather conditions turn unfavourable. Background emissions and local weather both shape how conditions change from day to day. Local weather patterns add further day-to-day variation.
Are air quality levels in San Miguel de Allende based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
Why doesn’t the forecast always reflect wildfire impacts?
Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.
During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.
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Data provided by Airmine — Last update: 21 September 2026 at 03:04 CEST (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
Disclaimer: Forecasts are provided for informational purposes only and should not be relied upon as medical advice. Actual pollen and air quality conditions may vary from the forecast. If you have allergies, asthma, or another medical condition, consult a healthcare professional. Please see our Terms of Service for important information about limitations of liability.
Some text on this page may be generated or summarised using artificial intelligence (AI). Wherever possible, AI-generated content is enriched with Airmine's proprietary data to improve its accuracy and relevance. However, AI-generated content may still contain errors, omissions, or inaccuracies.
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