Hourly Weather | Today Tuesday, March 17, 2026
St. Louis, Missouri
7 AM
Night
16°
Feels Like
13
Frost Risk: 100%
Humidity: 56%
UV Index: 0
Wind: 9 mph
8 AM
Sunny Weather
16°
Feels Like
0
Frost Risk: 100%
Humidity: 61%
UV Index: 1
Wind: 9 mph
9 AM
Sunny Weather
18°
Feels Like 12°
0
Frost Risk: 100%
Humidity: 56%
UV Index: 2
Wind: 8 mph
10 AM
Sunny Weather
19°
Feels Like 18°
0
Humidity: 52%
UV Index: 3
Wind: 7 mph
11 AM
Sunny Weather
23°
Feels Like 25°
0
Humidity: 46%
UV Index: 4
Wind: 7 mph
12 PM
Sunny Weather
25°
Feels Like 30°
0
Humidity: 42%
UV Index: 5
Wind: 7 mph
1 PM
Cloudy Weather
27°
Feels Like 34°
0
Humidity: 39%
UV Index: 5
Wind: 7 mph
2 PM
Cloudy Weather
30°
Feels Like 36°
7
Humidity: 36%
UV Index: 5
Wind: 6 mph
3 PM
Cloudy Weather
32°
Feels Like 37°
7
Humidity: 34%
UV Index: 4
Wind: 6 mph
4 PM
Cloudy Weather
34°
Feels Like 36°
7
Humidity: 33%
UV Index: 2
Wind: 5 mph
5 PM
Cloudy Weather
36°
Feels Like 34°
7
Humidity: 32%
UV Index: 1
Wind: 6 mph
6 PM
Cloudy Weather
34°
Feels Like 30°
7
Humidity: 35%
UV Index: 0
Wind: 6 mph
7 PM
Cloudy Weather
32°
Feels Like 27°
10
Humidity: 40%
UV Index: 0
Wind: 7 mph
8 PM
Snowy Weather
32°
Feels Like 27°
40
Humidity: 43%
UV Index: 0
Wind: 7 mph
9 PM
Snowy Weather
30°
Feels Like 23°
40
Humidity: 48%
UV Index: 0
Wind: 8 mph
10 PM
Cloudy Weather
30°
Feels Like 21°
36
Humidity: 54%
UV Index: 0
Wind: 9 mph
11 PM
Cloudy Weather
30°
Feels Like 23°
15
Humidity: 54%
UV Index: 0
Wind: 9 mph

Hourly Air Quality Forecast - AQI (US EPA)

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

Pollutant Concentrations:

  • PM2.5: 1.97 µg/m³
  • PM10: 2.26 µg/m³
  • O3: 0.049 ppm
  • NO2: 0.7 ppb
  • SO2: 0.6 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.97 µg/m³
  • PM10: 2.28 µg/m³
  • O3: 0.049 ppm
  • NO2: 0.8 ppb
  • SO2: 0.6 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.92 µg/m³
  • PM10: 2.24 µg/m³
  • O3: 0.049 ppm
  • NO2: 1.2 ppb
  • SO2: 0.6 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.86 µg/m³
  • PM10: 2.18 µg/m³
  • O3: 0.049 ppm
  • NO2: 1.1 ppb
  • SO2: 0.6 ppb
  • CO: 0.14 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.71 µg/m³
  • PM10: 2.01 µg/m³
  • O3: 0.051 ppm
  • NO2: 0.8 ppb
  • SO2: 0.6 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.69 µg/m³
  • PM10: 1.98 µg/m³
  • O3: 0.052 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: 1.8 µg/m³
  • PM10: 2.08 µg/m³
  • O3: 0.053 ppm
  • NO2: 0.5 ppb
  • SO2: 0.4 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.86 µg/m³
  • PM10: 2.16 µg/m³
  • O3: 0.055 ppm
  • NO2: 0.4 ppb
  • SO2: 0.3 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
57 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.79 µg/m³
  • PM10: 2.09 µg/m³
  • O3: 0.056 ppm
  • NO2: 0.3 ppb
  • SO2: 0.3 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
57 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.6 µg/m³
  • PM10: 1.91 µg/m³
  • O3: 0.056 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 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
59 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.46 µg/m³
  • PM10: 1.77 µg/m³
  • O3: 0.057 ppm
  • NO2: 0.3 ppb
  • SO2: 0.2 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.

6 PM
56 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.35 µg/m³
  • PM10: 1.67 µg/m³
  • O3: 0.056 ppm
  • NO2: 0.5 ppb
  • SO2: 0.2 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.

7 PM
52 AQI
Moderate air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.29 µg/m³
  • PM10: 1.62 µg/m³
  • O3: 0.055 ppm
  • NO2: 0.6 ppb
  • SO2: 0.2 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.

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

Pollutant Concentrations:

  • PM2.5: 1.28 µg/m³
  • PM10: 1.64 µg/m³
  • O3: 0.054 ppm
  • NO2: 0.7 ppb
  • SO2: 0.2 ppb
  • CO: 0.13 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.3 µg/m³
  • PM10: 1.7 µg/m³
  • O3: 0.053 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.

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

Pollutant Concentrations:

  • PM2.5: 1.39 µg/m³
  • PM10: 1.84 µg/m³
  • O3: 0.053 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.

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

Pollutant Concentrations:

  • PM2.5: 1.65 µg/m³
  • PM10: 2.18 µg/m³
  • O3: 0.054 ppm
  • NO2: 0.5 ppb
  • SO2: 0.2 ppb
  • CO: 0.13 ppm

Health Recommendations:

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