Hourly Weather | Today Monday, September 21, 2026
St. Peters, Missouri
2 PM
Cloudy Weather
73°
Feels Like 75°
7
Humidity: 77%
UV Index: 1
Wind: 7 mph
3 PM
Cloudy Weather
73°
Feels Like 75°
7
Humidity: 74%
UV Index: 1
Wind: 7 mph
4 PM
Cloudy Weather
73°
Feels Like 73°
7
Humidity: 74%
UV Index: 1
Wind: 8 mph
5 PM
Cloudy Weather
73°
Feels Like 72°
7
Humidity: 74%
UV Index: 1
Wind: 8 mph
6 PM
Cloudy Weather
72°
Feels Like 70°
7
Humidity: 74%
UV Index: 0
Wind: 8 mph
7 PM
Cloudy Weather
72°
Feels Like 68°
5
Humidity: 75%
UV Index: 0
Wind: 8 mph
8 PM
Cloudy Weather
70°
Feels Like 68°
0
Humidity: 82%
UV Index: 0
Wind: 7 mph
9 PM
Cloudy Weather
70°
Feels Like 68°
0
Humidity: 82%
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
68°
Feels Like 66°
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: 4.03 µg/m³
  • PM10: 4.09 µg/m³
  • O3: 0.032 ppm
  • NO2: 0.5 ppb
  • SO2: 0.1 ppb
  • CO: 0.12 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.85 µg/m³
  • PM10: 3.91 µg/m³
  • O3: 0.031 ppm
  • NO2: 0.5 ppb
  • SO2: 0.1 ppb
  • CO: 0.12 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.85 µg/m³
  • PM10: 3.91 µg/m³
  • O3: 0.029 ppm
  • NO2: 0.5 ppb
  • SO2: 0.1 ppb
  • CO: 0.12 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: 3.87 µg/m³
  • PM10: 3.93 µg/m³
  • O3: 0.026 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.

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

Pollutant Concentrations:

  • PM2.5: 3.93 µg/m³
  • PM10: 3.98 µg/m³
  • O3: 0.025 ppm
  • NO2: 0.8 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 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: 3.98 µg/m³
  • PM10: 4.03 µg/m³
  • O3: 0.024 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.

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

Pollutant Concentrations:

  • PM2.5: 4.11 µg/m³
  • PM10: 4.17 µg/m³
  • O3: 0.022 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.

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

Pollutant Concentrations:

  • PM2.5: 4.36 µg/m³
  • PM10: 4.43 µg/m³
  • O3: 0.020 ppm
  • NO2: 1.2 ppb
  • SO2: 0.1 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.66 µg/m³
  • PM10: 4.76 µg/m³
  • O3: 0.018 ppm
  • NO2: 1.5 ppb
  • SO2: 0.2 ppb
  • CO: 0.15 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 5.01 µg/m³
  • PM10: 5.16 µg/m³
  • O3: 0.016 ppm
  • NO2: 2 ppb
  • SO2: 0.4 ppb
  • CO: 0.16 ppm

Health Recommendations:

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