Hourly Weather | Today Monday, September 21, 2026
Castle Rock, Colorado
2 PM
Cloudy Weather
72°
Feels Like 75°
0
Humidity: 39%
UV Index: 5
Wind: 8 mph
3 PM
Cloudy Weather
73°
Feels Like 75°
0
Humidity: 35%
UV Index: 4
Wind: 9 mph
4 PM
Cloudy Weather
72°
Feels Like 73°
0
Humidity: 37%
UV Index: 3
Wind: 9 mph
5 PM
Cloudy Weather
70°
Feels Like 70°
0
Humidity: 42%
UV Index: 2
Wind: 9 mph
6 PM
Cloudy Weather
66°
Feels Like 64°
0
Humidity: 48%
UV Index: 1
Wind: 9 mph
7 PM
Cloudy Night
63°
Feels Like 61°
0
Humidity: 55%
UV Index: 0
Wind: 9 mph
8 PM
Cloudy Night
61°
Feels Like 57°
47
Humidity: 63%
UV Index: 0
Wind: 9 mph
9 PM
Stormy Weather
59°
Feels Like 54°
51
Humidity: 71%
UV Index: 0
Wind: 9 mph
10 PM
Cloudy Night
57°
Feels Like 54°
47
Humidity: 77%
UV Index: 0
Wind: 9 mph
11 PM
Cloudy Night
55°
Feels Like 52°
19
Humidity: 81%
UV Index: 0
Wind: 9 mph

Hourly Air Quality Forecast - AQI (US EPA)

2 PM
43 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.83 µg/m³
  • PM10: 2.93 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.75 µg/m³
  • PM10: 2.76 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.68 µg/m³
  • PM10: 2.62 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.59 µg/m³
  • PM10: 2.45 µg/m³
  • O3: 0.048 ppm
  • NO2: 0.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.54 µg/m³
  • PM10: 2.41 µg/m³
  • O3: 0.048 ppm
  • NO2: 0.1 ppb
  • SO2: 0.1 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.46 µg/m³
  • PM10: 2.33 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.2 ppb
  • SO2: 0.1 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.35 µg/m³
  • PM10: 2.22 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.4 ppb
  • SO2: 0.1 ppb
  • CO: 0.08 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.29 µg/m³
  • PM10: 2.22 µg/m³
  • O3: 0.043 ppm
  • NO2: 0.5 ppb
  • SO2: 0.1 ppb
  • CO: 0.08 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.28 µg/m³
  • PM10: 2.31 µg/m³
  • O3: 0.040 ppm
  • NO2: 0.5 ppb
  • SO2: 0.1 ppb
  • CO: 0.08 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.32 µg/m³
  • PM10: 2.54 µg/m³
  • O3: 0.037 ppm
  • NO2: 0.6 ppb
  • SO2: 0.1 ppb
  • CO: 0.08 ppm

Health Recommendations:

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