Hourly Weather | Today Tuesday, September 16, 2025
Active Weather Warnings
St. Louis, Missouri
3 AM
Cloudy Night
70°
Feels Like 68°
0
Humidity: 88%
Wind: 5 mph
UV Index: 0
4 AM
Night
66°
Feels Like 66°
0
Humidity: 92%
Wind: 5 mph
UV Index: 0
5 AM
Night
66°
Feels Like 66°
0
Humidity: 94%
Wind: 5 mph
UV Index: 0
6 AM
Night
64°
Feels Like 64°
0
Humidity: 96%
Wind: 5 mph
UV Index: 0
7 AM
Sunny Weather
64°
Feels Like 66°
0
Humidity: 98%
Wind: 5 mph
UV Index: 1
8 AM
Sunny Weather
68°
Feels Like 70°
0
Humidity: 87%
Wind: 5 mph
UV Index: 11
9 AM
Sunny Weather
75°
Feels Like 79°
0
Humidity: 72%
Wind: 6 mph
UV Index: 20
10 AM
Sunny Weather
81°
Feels Like 84°
0
Humidity: 59%
Wind: 6 mph
UV Index: 31
11 AM
Sunny Weather
84°
Feels Like 90°
0
Humidity: 51%
Wind: 6 mph
UV Index: 43
12 PM
Sunny Weather
88°
Feels Like 93°
0
Humidity: 44%
Wind: 6 mph
UV Index: 52
1 PM
Sunny Weather
90°
Feels Like 95°
0
Humidity: 39%
Wind: 7 mph
UV Index: 58
2 PM
Sunny Weather
91°
Feels Like 97°
0
Humidity: 35%
Wind: 7 mph
UV Index: 52
3 PM
Sunny Weather
93°
Feels Like 97°
0
Humidity: 32%
Wind: 7 mph
UV Index: 43
4 PM
Sunny Weather
93°
Feels Like 93°
0
Humidity: 33%
Wind: 7 mph
UV Index: 31
5 PM
Sunny Weather
91°
Feels Like 91°
0
Humidity: 33%
Wind: 7 mph
UV Index: 20
6 PM
Cloudy Weather
90°
Feels Like 90°
0
Humidity: 34%
Wind: 7 mph
UV Index: 11
7 PM
Cloudy Weather
88°
Feels Like 84°
0
Humidity: 39%
Wind: 7 mph
UV Index: 1
8 PM
Night
82°
Feels Like 81°
0
Humidity: 44%
Wind: 6 mph
UV Index: 0
9 PM
Night
81°
Feels Like 79°
0
Humidity: 49%
Wind: 6 mph
UV Index: 0
10 PM
Night
79°
Feels Like 75°
0
Humidity: 54%
Wind: 6 mph
UV Index: 0
11 PM
Night
75°
Feels Like 73°
0
Humidity: 60%
Wind: 5 mph
UV Index: 0

Hourly Air Quality Forecast - AQI (US EPA)

3 AM
63 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 14.25 µg/m³
  • PM10: 14.53 µg/m³
  • O₃: 37.06 ppb
  • NO₂: 7.57 ppb
  • SO₂: 4.12 ppb
  • CO: 228.14 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

4 AM
63 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 13.99 µg/m³
  • PM10: 14.26 µg/m³
  • O₃: 36.33 ppb
  • NO₂: 6.99 ppb
  • SO₂: 4.32 ppb
  • CO: 219.10 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

5 AM
63 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 13.92 µg/m³
  • PM10: 14.20 µg/m³
  • O₃: 32.97 ppb
  • NO₂: 8.50 ppb
  • SO₂: 4.13 ppb
  • CO: 227.72 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

6 AM
63 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 14.04 µg/m³
  • PM10: 14.32 µg/m³
  • O₃: 29.60 ppb
  • NO₂: 10.02 ppb
  • SO₂: 3.94 ppb
  • CO: 236.34 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

7 AM
63 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 14.39 µg/m³
  • PM10: 14.65 µg/m³
  • O₃: 26.24 ppb
  • NO₂: 11.53 ppb
  • SO₂: 3.75 ppb
  • CO: 244.96 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

8 AM
63 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 14.75 µg/m³
  • PM10: 14.97 µg/m³
  • O₃: 36.05 ppb
  • NO₂: 9.47 ppb
  • SO₂: 4.02 ppb
  • CO: 243.74 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

9 AM
63 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 13.63 µg/m³
  • PM10: 13.86 µg/m³
  • O₃: 45.86 ppb
  • NO₂: 7.41 ppb
  • SO₂: 4.30 ppb
  • CO: 242.51 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

10 AM
63 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 14.04 µg/m³
  • PM10: 14.31 µg/m³
  • O₃: 55.67 ppb
  • NO₂: 5.35 ppb
  • SO₂: 4.57 ppb
  • CO: 241.28 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

11 AM
63 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 14.24 µg/m³
  • PM10: 14.60 µg/m³
  • O₃: 62.89 ppb
  • NO₂: 3.90 ppb
  • SO₂: 3.90 ppb
  • CO: 219.05 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

12 PM
62 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 12.44 µg/m³
  • PM10: 12.83 µg/m³
  • O₃: 70.12 ppb
  • NO₂: 2.46 ppb
  • SO₂: 3.23 ppb
  • CO: 196.81 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

1 PM
62 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 11.19 µg/m³
  • PM10: 11.59 µg/m³
  • O₃: 77.34 ppb
  • NO₂: 1.01 ppb
  • SO₂: 2.56 ppb
  • CO: 174.57 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

2 PM
61 AQI
Moderate air quality Dominant pollutant: pm25
Details

Pollutant Concentrations:

  • PM2.5: 10.76 µg/m³
  • PM10: 11.14 µg/m³
  • O₃: 77.80 ppb
  • NO₂: 1.04 ppb
  • SO₂: 2.36 ppb
  • CO: 172.49 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

3 PM
77 AQI
Moderate air quality Dominant pollutant: o3
Details

Pollutant Concentrations:

  • PM2.5: 10.53 µg/m³
  • PM10: 10.93 µg/m³
  • O₃: 78.26 ppb
  • NO₂: 1.08 ppb
  • SO₂: 2.17 ppb
  • CO: 170.41 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

4 PM
94 AQI
Moderate air quality Dominant pollutant: o3
Details

Pollutant Concentrations:

  • PM2.5: 10.40 µg/m³
  • PM10: 10.80 µg/m³
  • O₃: 78.72 ppb
  • NO₂: 1.11 ppb
  • SO₂: 1.98 ppb
  • CO: 168.33 ppb

Health Recommendations:

Air quality is currently in the acceptable range. However, sensitive individuals should be aware of potential risks from certain pollutants.

5 PM
104 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: o3
Details

Pollutant Concentrations:

  • PM2.5: 10.35 µg/m³
  • PM10: 10.74 µg/m³
  • O₃: 74.39 ppb
  • NO₂: 2.71 ppb
  • SO₂: 1.97 ppb
  • CO: 181.57 ppb

Health Recommendations:

Air quality may be unhealthy for sensitive groups. The general public is not likely to be affected.

6 PM
110 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: o3
Details

Pollutant Concentrations:

  • PM2.5: 10.46 µg/m³
  • PM10: 10.83 µg/m³
  • O₃: 70.05 ppb
  • NO₂: 4.30 ppb
  • SO₂: 1.95 ppb
  • CO: 194.82 ppb

Health Recommendations:

Air quality may be unhealthy for sensitive groups. The general public is not likely to be affected.

7 PM
111 AQI
Unhealthy air quality for sensitive groups Dominant pollutant: o3
Details

Pollutant Concentrations:

  • PM2.5: 11.84 µg/m³
  • PM10: 12.15 µg/m³
  • O₃: 65.71 ppb
  • NO₂: 5.90 ppb
  • SO₂: 1.94 ppb
  • CO: 208.07 ppb

Health Recommendations:

Air quality may be unhealthy for sensitive groups. The general public is not likely to be affected.

Weather Alerts and Warnings for St. Louis

Air Quality Alert

Air Quality Alert issued September 15 at 1:53PM CDT by NWS St Louis MO
Sep 15, 1:53 PM Sep 16, 2:00 PM
The St. Louis Clean Air Partnership has issued an air quality alert
for the St. Louis metropolitan area until 8 PM CDT this evening.

An Orange air quality forecast means that maximum ozone
concentrations are expected to reach levels that pose a health risk.
Adverse health effects increase as air quality deteriorates. Ground-
level ozone is an air contaminant which can cause breathing
difficulties for children, older adults, as well as persons with
respiratory problems.

Reducing outdoor physical activity is recommended. If it is a
regularly scheduled work day you are urged to consider
telecommuting, carpooling, or utilizing public transit. Avoid
excessive idling and do not top off when refueling motor vehicles.
The use of gasoline-powered lawn equipment should be reduced or
postponed until late in the day.

For more information visit the St. Louis Clean Air Partnership at
http://cleanair-stlouis.com/

For current Air Quality Index (AQI) values visit
https://www.airnow.gov/
Updated: Sep 16, 12:48 AM Source: NWS Alert