Hourly Weather | Today Monday, September 21, 2026
O'Fallon, Missouri
2 PM
Cloudy Weather
73°
Feels Like 73°
7
Humidity: 77%
UV Index: 1
Wind: 7 mph
3 PM
Cloudy Weather
73°
Feels Like 73°
7
Humidity: 75%
UV Index: 1
Wind: 7 mph
4 PM
Cloudy Weather
73°
Feels Like 73°
7
Humidity: 75%
UV Index: 1
Wind: 8 mph
5 PM
Cloudy Weather
72°
Feels Like 72°
7
Humidity: 75%
UV Index: 1
Wind: 8 mph
6 PM
Cloudy Weather
72°
Feels Like 70°
7
Humidity: 75%
UV Index: 0
Wind: 8 mph
7 PM
Cloudy Weather
70°
Feels Like 68°
5
Humidity: 76%
UV Index: 0
Wind: 7 mph
8 PM
Cloudy Weather
70°
Feels Like 66°
0
Humidity: 82%
UV Index: 0
Wind: 7 mph
9 PM
Cloudy Weather
68°
Feels Like 66°
0
Humidity: 83%
UV Index: 0
Wind: 7 mph
10 PM
Cloudy Weather
68°
Feels Like 66°
0
Humidity: 83%
UV Index: 0
Wind: 7 mph
11 PM
Cloudy Weather
66°
Feels Like 64°
0
Humidity: 83%
UV Index: 0
Wind: 7 mph

Hourly Air Quality Forecast - AQI (US EPA)

2 PM
30 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.55 µg/m³
  • PM10: 4.62 µg/m³
  • O3: 0.032 ppm
  • NO2: 0.6 ppb
  • SO2: 0.2 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

3 PM
28 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.33 µg/m³
  • PM10: 4.39 µg/m³
  • O3: 0.031 ppm
  • NO2: 0.6 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

4 PM
26 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.29 µg/m³
  • PM10: 4.35 µg/m³
  • O3: 0.028 ppm
  • NO2: 0.6 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

5 PM
24 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.28 µg/m³
  • PM10: 4.35 µg/m³
  • O3: 0.026 ppm
  • NO2: 0.7 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

6 PM
23 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.36 µg/m³
  • PM10: 4.43 µg/m³
  • O3: 0.025 ppm
  • NO2: 0.9 ppb
  • SO2: 0.1 ppb
  • CO: 0.14 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

7 PM
22 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.43 µg/m³
  • PM10: 4.5 µg/m³
  • O3: 0.024 ppm
  • NO2: 1 ppb
  • SO2: 0.1 ppb
  • CO: 0.14 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

8 PM
21 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.55 µg/m³
  • PM10: 4.63 µg/m³
  • O3: 0.022 ppm
  • NO2: 1.2 ppb
  • SO2: 0.1 ppb
  • CO: 0.15 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

9 PM
20 AQI
Good air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 4.77 µg/m³
  • PM10: 4.86 µg/m³
  • O3: 0.020 ppm
  • NO2: 1.5 ppb
  • SO2: 0.2 ppb
  • CO: 0.16 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

10 PM
21 AQI
Good air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 5 µg/m³
  • PM10: 5.14 µg/m³
  • O3: 0.017 ppm
  • NO2: 2 ppb
  • SO2: 0.3 ppb
  • CO: 0.16 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

11 PM
22 AQI
Good air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 5.29 µg/m³
  • PM10: 5.49 µg/m³
  • O3: 0.016 ppm
  • NO2: 2.5 ppb
  • SO2: 0.6 ppb
  • CO: 0.17 ppm

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.