Worst air pollution Modesto, today and tomorrow
Today (15 July): Air quality in Modesto is fair. AQI, PM2.5, NO2, and O3 are fair; PM10, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 8:00 AM (O3: 39.4/100).
Tomorrow (16 July 2026): Air quality in Modesto is fair. AQI improves to medium; O3 decreases to medium; PM1 increases to fair; all other pollutants stay as today. Pollution peaks around 10:00 AM (O3: 41.0/100). 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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Modesto's air quality reflects the San Joaquin Valley's enclosed basin position, sharing the valley's notorious pollution trap with Fresno and Stockton but benefiting slightly from the Delta breeze corridor that provides afternoon ventilation from San Francisco Bay. Vehicle emissions from CA-99 and agricultural emissions from the surrounding Central Valley dairy and almond farming operations contribute to the persistent winter inversion and summer ozone challenges.
Today - 15 July | Pollution peaks at 08:00
AQI:
Fair
39.4/100
PM2.5 (fine particles):
Fair
21.9/100
PM10 (coarse particles):
Good
13.6/100
NO2 (nitrogen dioxide):
Fair
20.8/100
O3 (ozone):
Fair
39.4/100
SO2 (sulfur dioxide):
Good
9.1/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.2/100
PM1 (ultrafine particles):
Good
12.1/100
Levels show the poorest local air quality during the day
Tomorrow - 16 July | Pollution peaks at 10:00
AQI:
Medium
41.0/100
PM2.5 (fine particles):
Fair
29.5/100
PM10 (coarse particles):
Good
15.0/100
NO2 (nitrogen dioxide):
Fair
38.5/100
O3 (ozone):
Medium
41.0/100
SO2 (sulfur dioxide):
Good
9.1/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
1.9/100
PM1 (ultrafine particles):
Fair
20.2/100
Pollen forecast in Modesto
View pollen forecastFrequently Asked Questions
Is air quality bad in Modesto right now?
On 15 July 2026, overall air quality in Modesto is fair. AQI is the main air quality indicator at 39.4/100. Pollution peaks around 8:00 AM (O3: 39.4/100).
Will air quality be worse tomorrow in Modesto?
On 16 July 2026, air quality conditions in Modesto will be similar to today, with NO2 forecast at fair at 38.5/100. Pollution peaks around 10:00 AM (O3: 41.0/100).
When is air pollution at its worst in Modesto?
Air quality in Modesto shifts across the year. In short, spring typically offers the best combination of mild weather and clear air, whereas heat and dryness combine from July onward to raise both ozone and smoke risk. Dry summer conditions with virtually no rain mean pollution and smoke can linger for extended stretches once they arrive.
Are air quality levels in Modesto 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.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 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.
For long term forecasts and maps, see the Airmine app