Air Quality in O'Fallon, United States
Windy
8.3°C · 86.6% humidity
8.3°
Feels 2.5°
28
Good
Air quality is satisfactory. Enjoy outdoor activities.
Calibrated model
Nearby Monitoring Stations
O'Fallon's air quality — share it
AQI Forecast
25
6am
25
25
28
9am
25
27
27
12pm
27
27
27
3pm
25
25
25
6pm
25
34
54
9pm
54
54
54
12am
54
34
34
3am
27
27
Air Quality Index Trend
46h · 4 stnO'Fallon's air quality is primarily affected by vehicle emissions and industrial activity. Seasonal wildfire smoke and weather patterns can cause periodic air quality deterioration. Current PM2.5 concentration in O'Fallon is 1.3× the WHO annual guideline of 5 µg/m³.
86.6%
Humidity
64.1 km/h
Wind NNE
1027.1 hPa
Pressure
5.9
UV High
GoodModerateUSGUnhealthyVery UnhealthyHazardous
Which pollutant is driving the AQI?
PM2.5▲
6.74 µg/m³
PM10
13.7 µg/m³
050100150200300500
What is the weather forecast for O'Fallon?
Temperature & Precipitation
PM2.5 Trend
46h · 4 stationsPM2.56.74 µg/m³
✓ WHO
Good
PM1013.7 µg/m³
Good
UV INDEX5.9
High
What is the 7-day forecast for O'Fallon?
05-29
30.1° 8.3°
1.31 mm
05-30
28.3° 18.8°
3.38 mm
05-31
31.1° 11.9°
06-01
30.8° 17.5°
0.06 mm
06-02
26.2° 13.8°
06-03
29.8° 23.3°
0.44 mm
06-04
26.7° 20.3°
3.88 mm
Both models agree
Avg diff: 4.0°C
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Data sources: AQI from ground-level monitoring stations via AQICN. Weather forecast from ECMWF (IFS & CAMS models). AQI calculated using US EPA standard. Updated 2026-05-29T14:49 UTC.