Hourly Weather | Today Saturday, September 19, 2026
Boulder, Colorado
4 AM
Cloudy Night
55°
Feels Like 54°
14
Humidity: 83%
UV Index: 0
Wind: 6 mph
5 AM
Cloudy Night
55°
Feels Like 54°
14
Humidity: 84%
UV Index: 0
Wind: 6 mph
6 AM
Cloudy Night
54°
Feels Like 52°
14
Humidity: 84%
UV Index: 0
Wind: 6 mph
7 AM
Cloudy Weather
57°
Feels Like 55°
11
Humidity: 77%
UV Index: 0
Wind: 6 mph
8 AM
Cloudy Weather
61°
Feels Like 63°
7
Humidity: 70%
UV Index: 1
Wind: 5 mph
9 AM
Cloudy Weather
66°
Feels Like 68°
7
Humidity: 60%
UV Index: 2
Wind: 4 mph
10 AM
Cloudy Weather
72°
Feels Like 73°
7
Humidity: 52%
UV Index: 3
Wind: 5 mph
11 AM
Cloudy Weather
73°
Feels Like 77°
7
Humidity: 47%
UV Index: 4
Wind: 6 mph
12 PM
Cloudy Weather
75°
Feels Like 81°
7
Humidity: 43%
UV Index: 5
Wind: 6 mph
1 PM
Cloudy Weather
77°
Feels Like 82°
10
Humidity: 41%
UV Index: 5
Wind: 6 mph
2 PM
Sunny with a Chance of Thunderstorms
73°
Feels Like 70°
56
Humidity: 58%
UV Index: 2
Wind: 6 mph
3 PM
Cloudy Weather
72°
Feels Like 75°
49
Humidity: 60%
UV Index: 4
Wind: 6 mph
4 PM
Cloudy Weather
70°
Feels Like 72°
47
Humidity: 62%
UV Index: 3
Wind: 6 mph
5 PM
Cloudy Weather
70°
Feels Like 70°
43
Humidity: 54%
UV Index: 2
Wind: 6 mph
6 PM
Cloudy Weather
68°
Feels Like 66°
47
Humidity: 58%
UV Index: 1
Wind: 6 mph
7 PM
Stormy Weather
64°
Feels Like 59°
51
Humidity: 75%
UV Index: 0
Wind: 6 mph
8 PM
Stormy Weather
63°
Feels Like 59°
51
Humidity: 78%
UV Index: 0
Wind: 6 mph
9 PM
Cloudy Weather
61°
Feels Like 61°
47
Humidity: 80%
UV Index: 0
Wind: 6 mph
10 PM
Cloudy Night
61°
Feels Like 59°
40
Humidity: 76%
UV Index: 0
Wind: 5 mph
11 PM
Cloudy Night
57°
Feels Like 57°
34
Humidity: 77%
UV Index: 0
Wind: 5 mph

Hourly Air Quality Forecast - AQI (US EPA)

4 AM
12 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.65 µg/m³
  • PM10: 0.69 µg/m³
  • O3: 0.013 ppm
  • NO2: 1.3 ppb
  • SO2: 0 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

5 AM
12 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.7 µg/m³
  • PM10: 0.74 µg/m³
  • O3: 0.013 ppm
  • NO2: 1.3 ppb
  • SO2: 0 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.75 µg/m³
  • PM10: 0.79 µg/m³
  • O3: 0.013 ppm
  • NO2: 1.2 ppb
  • SO2: 0 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.72 µg/m³
  • PM10: 0.77 µg/m³
  • O3: 0.012 ppm
  • NO2: 1.3 ppb
  • SO2: 0 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.66 µg/m³
  • PM10: 0.71 µg/m³
  • O3: 0.012 ppm
  • NO2: 1.4 ppb
  • SO2: 0 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.66 µg/m³
  • PM10: 0.72 µg/m³
  • O3: 0.013 ppm
  • NO2: 1 ppb
  • SO2: 0 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.65 µg/m³
  • PM10: 0.88 µg/m³
  • O3: 0.026 ppm
  • NO2: 0.3 ppb
  • SO2: 0 ppb
  • CO: 0.08 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.67 µg/m³
  • PM10: 0.99 µg/m³
  • O3: 0.027 ppm
  • NO2: 0.1 ppb
  • SO2: 0 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.67 µg/m³
  • PM10: 1.03 µg/m³
  • O3: 0.027 ppm
  • NO2: 0.1 ppb
  • SO2: 0 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.67 µg/m³
  • PM10: 1.15 µg/m³
  • O3: 0.028 ppm
  • NO2: 0.1 ppb
  • SO2: 0 ppb
  • CO: 0.06 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.69 µg/m³
  • PM10: 1.28 µg/m³
  • O3: 0.027 ppm
  • NO2: 0 ppb
  • SO2: 0 ppb
  • CO: 0.06 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.74 µg/m³
  • PM10: 1.43 µg/m³
  • O3: 0.027 ppm
  • NO2: 0 ppb
  • SO2: 0 ppb
  • CO: 0.06 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.8 µg/m³
  • PM10: 1.61 µg/m³
  • O3: 0.028 ppm
  • NO2: 0.1 ppb
  • SO2: 0 ppb
  • CO: 0.06 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.88 µg/m³
  • PM10: 1.84 µg/m³
  • O3: 0.028 ppm
  • NO2: 0.1 ppb
  • SO2: 0 ppb
  • CO: 0.06 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.93 µg/m³
  • PM10: 2.09 µg/m³
  • O3: 0.028 ppm
  • NO2: 0.1 ppb
  • SO2: 0 ppb
  • CO: 0.06 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.97 µg/m³
  • PM10: 2.15 µg/m³
  • O3: 0.026 ppm
  • NO2: 0.4 ppb
  • SO2: 0 ppb
  • CO: 0.06 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1 µg/m³
  • PM10: 2.16 µg/m³
  • O3: 0.024 ppm
  • NO2: 0.7 ppb
  • SO2: 0 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.04 µg/m³
  • PM10: 2.23 µg/m³
  • O3: 0.023 ppm
  • NO2: 0.8 ppb
  • SO2: 0 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.05 µg/m³
  • PM10: 2.23 µg/m³
  • O3: 0.022 ppm
  • NO2: 1 ppb
  • SO2: 0 ppb
  • CO: 0.07 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 1.07 µg/m³
  • PM10: 2.27 µg/m³
  • O3: 0.020 ppm
  • NO2: 1.2 ppb
  • SO2: 0 ppb
  • CO: 0.07 ppm

Health Recommendations:

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