Hourly Weather | Today Monday, September 21, 2026
Decatur, Illinois
3 PM
Cloudy Weather
66°
Feels Like 64°
34
Humidity: 82%
UV Index: 2
Wind: 10 mph
4 PM
Cloudy Weather
66°
Feels Like 64°
34
Humidity: 75%
UV Index: 1
Wind: 10 mph
5 PM
Cloudy Weather
66°
Feels Like 64°
35
Humidity: 75%
UV Index: 1
Wind: 10 mph
6 PM
Cloudy Weather
66°
Feels Like 63°
38
Humidity: 75%
UV Index: 0
Wind: 9 mph
7 PM
Rainy Night
64°
Feels Like 61°
42
Humidity: 76%
UV Index: 0
Wind: 9 mph
8 PM
Cloudy Weather
64°
Feels Like 63°
10
Humidity: 78%
UV Index: 0
Wind: 10 mph
9 PM
Cloudy Weather
64°
Feels Like 61°
7
Humidity: 80%
UV Index: 0
Wind: 9 mph
10 PM
Cloudy Weather
63°
Feels Like 61°
7
Humidity: 81%
UV Index: 0
Wind: 9 mph
11 PM
Cloudy Weather
63°
Feels Like 59°
7
Humidity: 82%
UV Index: 0
Wind: 9 mph

Hourly Air Quality Forecast - AQI (US EPA)

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

Pollutant Concentrations:

  • PM2.5: 3.02 µg/m³
  • PM10: 3.17 µg/m³
  • O3: 0.030 ppm
  • NO2: 2 ppb
  • SO2: 0.8 ppb
  • CO: 0.16 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.26 µg/m³
  • PM10: 3.42 µg/m³
  • O3: 0.032 ppm
  • NO2: 1.9 ppb
  • SO2: 0.7 ppb
  • CO: 0.16 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.41 µg/m³
  • PM10: 3.58 µg/m³
  • O3: 0.032 ppm
  • NO2: 2 ppb
  • SO2: 0.7 ppb
  • CO: 0.16 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.5 µg/m³
  • PM10: 3.69 µg/m³
  • O3: 0.032 ppm
  • NO2: 2.1 ppb
  • SO2: 0.7 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.55 µg/m³
  • PM10: 3.77 µg/m³
  • O3: 0.032 ppm
  • NO2: 2.2 ppb
  • SO2: 0.6 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.58 µg/m³
  • PM10: 3.82 µg/m³
  • O3: 0.032 ppm
  • NO2: 2.1 ppb
  • SO2: 0.6 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.68 µg/m³
  • PM10: 3.94 µg/m³
  • O3: 0.032 ppm
  • NO2: 2.1 ppb
  • SO2: 0.6 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.75 µg/m³
  • PM10: 4.05 µg/m³
  • O3: 0.031 ppm
  • NO2: 2.1 ppb
  • SO2: 0.6 ppb
  • CO: 0.17 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 3.74 µg/m³
  • PM10: 4.07 µg/m³
  • O3: 0.029 ppm
  • NO2: 2.2 ppb
  • SO2: 0.6 ppb
  • CO: 0.18 ppm

Health Recommendations:

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