Hourly Weather | Today Wednesday, March 18, 2026
St. Charles, Missouri
6 AM
Cloudy Weather
34°
Feels Like 28°
34
Humidity: 65%
UV Index: 0
Wind: 8 mph
7 AM
Cloudy Weather
36°
Feels Like 30°
22
Humidity: 67%
UV Index: 0
Wind: 8 mph
8 AM
Cloudy Weather
34°
Feels Like 27°
0
Humidity: 66%
UV Index: 1
Wind: 10 mph
9 AM
Cloudy Weather
37°
Feels Like 32°
0
Humidity: 65%
UV Index: 2
Wind: 10 mph
10 AM
Cloudy Weather
43°
Feels Like 39°
0
Humidity: 58%
UV Index: 3
Wind: 9 mph
11 AM
Sunny Weather
48°
Feels Like 48°
0
Humidity: 51%
UV Index: 4
Wind: 9 mph
12 PM
Sunny Weather
52°
Feels Like 55°
0
Humidity: 46%
UV Index: 5
Wind: 9 mph
1 PM
Sunny Weather
55°
Feels Like 61°
0
Humidity: 43%
UV Index: 5
Wind: 9 mph
2 PM
Sunny Weather
61°
Feels Like 63°
0
Humidity: 40%
UV Index: 5
Wind: 8 mph
3 PM
Cloudy Weather
63°
Feels Like 64°
0
Humidity: 38%
UV Index: 4
Wind: 9 mph
4 PM
Cloudy Weather
63°
Feels Like 64°
0
Humidity: 39%
UV Index: 3
Wind: 8 mph
5 PM
Cloudy Weather
64°
Feels Like 66°
0
Humidity: 39%
UV Index: 2
Wind: 7 mph
6 PM
Cloudy Weather
61°
Feels Like 63°
0
Humidity: 45%
UV Index: 1
Wind: 6 mph
7 PM
Cloudy Weather
59°
Feels Like 57°
0
Humidity: 52%
UV Index: 0
Wind: 5 mph
8 PM
Cloudy Night
55°
Feels Like 55°
0
Humidity: 58%
UV Index: 0
Wind: 5 mph
9 PM
Cloudy Night
54°
Feels Like 52°
0
Humidity: 64%
UV Index: 0
Wind: 5 mph
10 PM
Cloudy Night
50°
Feels Like 48°
0
Humidity: 71%
UV Index: 0
Wind: 5 mph
11 PM
Cloudy Night
46°
Feels Like 46°
0
Humidity: 78%
UV Index: 0
Wind: 5 mph

Hourly Air Quality Forecast - AQI (US EPA)

6 AM
45 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 3.38 µg/m³
  • PM10: 4.13 µg/m³
  • O3: 0.049 ppm
  • NO2: 0.6 ppb
  • SO2: 0.5 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

7 AM
44 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 3.46 µg/m³
  • PM10: 4.11 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.6 ppb
  • SO2: 0.4 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

8 AM
43 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 3.5 µg/m³
  • PM10: 4.15 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.7 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

9 AM
42 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 3.52 µg/m³
  • PM10: 4.34 µg/m³
  • O3: 0.046 ppm
  • NO2: 1 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

10 AM
43 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 3.98 µg/m³
  • PM10: 5.08 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.9 ppb
  • SO2: 0.4 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

11 AM
46 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.87 µg/m³
  • PM10: 6.25 µg/m³
  • O3: 0.049 ppm
  • NO2: 0.7 ppb
  • SO2: 0.5 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

12 PM
47 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.11 µg/m³
  • PM10: 6.61 µg/m³
  • O3: 0.051 ppm
  • NO2: 0.6 ppb
  • SO2: 0.5 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

1 PM
49 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.64 µg/m³
  • PM10: 6.19 µg/m³
  • O3: 0.053 ppm
  • NO2: 0.4 ppb
  • SO2: 0.5 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

2 PM
59 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.41 µg/m³
  • PM10: 6 µg/m³
  • O3: 0.057 ppm
  • NO2: 0.3 ppb
  • SO2: 0.5 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

3 PM
62 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.37 µg/m³
  • PM10: 5.92 µg/m³
  • O3: 0.058 ppm
  • NO2: 0.3 ppb
  • SO2: 0.4 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

4 PM
62 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 4.25 µg/m³
  • PM10: 5.71 µg/m³
  • O3: 0.058 ppm
  • NO2: 0.3 ppb
  • SO2: 0.4 ppb
  • CO: 0.12 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

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

Pollutant Concentrations:

  • PM2.5: 4.34 µg/m³
  • PM10: 5.65 µg/m³
  • O3: 0.054 ppm
  • NO2: 0.6 ppb
  • SO2: 0.3 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.57 µg/m³
  • PM10: 5.78 µg/m³
  • O3: 0.047 ppm
  • NO2: 1.3 ppb
  • SO2: 0.2 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.75 µg/m³
  • PM10: 5.94 µg/m³
  • O3: 0.042 ppm
  • NO2: 2.4 ppb
  • SO2: 0.2 ppb
  • CO: 0.15 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 4.92 µg/m³
  • PM10: 6.13 µg/m³
  • O3: 0.038 ppm
  • NO2: 3.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.16 ppm

Health Recommendations:

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

9 PM
33 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.15 µg/m³
  • PM10: 6.39 µg/m³
  • O3: 0.036 ppm
  • NO2: 3.3 ppb
  • SO2: 0.1 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

10 PM
31 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.38 µg/m³
  • PM10: 6.64 µg/m³
  • O3: 0.034 ppm
  • NO2: 3.2 ppb
  • SO2: 0.1 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

11 PM
31 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.52 µg/m³
  • PM10: 6.83 µg/m³
  • O3: 0.033 ppm
  • NO2: 2.7 ppb
  • SO2: 0.1 ppb
  • CO: 0.17 ppm

Health Recommendations:

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