Hourly Weather | Today Saturday, September 19, 2026
Longmont, Colorado
5 AM
Cloudy Night
55°
Feels Like 54°
13
Humidity: 91%
UV Index: 0
Wind: 5 mph
6 AM
Cloudy Night
54°
Feels Like 54°
13
Humidity: 91%
UV Index: 0
Wind: 5 mph
7 AM
Cloudy Weather
55°
Feels Like 55°
11
Humidity: 86%
UV Index: 0
Wind: 5 mph
8 AM
Cloudy Weather
59°
Feels Like 61°
7
Humidity: 81%
UV Index: 1
Wind: 5 mph
9 AM
Cloudy Weather
63°
Feels Like 66°
7
Humidity: 73%
UV Index: 2
Wind: 5 mph
10 AM
Cloudy Weather
68°
Feels Like 72°
7
Humidity: 59%
UV Index: 3
Wind: 6 mph
11 AM
Cloudy Weather
73°
Feels Like 75°
7
Humidity: 49%
UV Index: 4
Wind: 6 mph
12 PM
Cloudy Weather
77°
Feels Like 81°
7
Humidity: 43%
UV Index: 5
Wind: 7 mph
1 PM
Cloudy Weather
79°
Feels Like 82°
10
Humidity: 39%
UV Index: 5
Wind: 7 mph
2 PM
Sunny with a Chance of Thunderstorms
75°
Feels Like 73°
54
Humidity: 46%
UV Index: 2
Wind: 7 mph
3 PM
Cloudy Weather
73°
Feels Like 75°
49
Humidity: 50%
UV Index: 4
Wind: 8 mph
4 PM
Cloudy Weather
73°
Feels Like 75°
45
Humidity: 48%
UV Index: 3
Wind: 8 mph
5 PM
Cloudy Weather
72°
Feels Like 72°
47
Humidity: 50%
UV Index: 2
Wind: 8 mph
6 PM
Sunny with a Chance of Thunderstorms
70°
Feels Like 64°
51
Humidity: 58%
UV Index: 0
Wind: 8 mph
7 PM
Cloudy Weather
68°
Feels Like 64°
43
Humidity: 62%
UV Index: 0
Wind: 7 mph
8 PM
Stormy Weather
64°
Feels Like 61°
51
Humidity: 69%
UV Index: 0
Wind: 6 mph
9 PM
Cloudy Weather
63°
Feels Like 63°
47
Humidity: 73%
UV Index: 0
Wind: 6 mph
10 PM
Cloudy Night
61°
Feels Like 59°
40
Humidity: 79%
UV Index: 0
Wind: 6 mph
11 PM
Cloudy Night
61°
Feels Like 59°
34
Humidity: 79%
UV Index: 0
Wind: 6 mph

Hourly Air Quality Forecast - AQI (US EPA)

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

Pollutant Concentrations:

  • PM2.5: 0.72 µg/m³
  • PM10: 0.76 µg/m³
  • O3: 0.013 ppm
  • NO2: 1.5 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: 0.81 µg/m³
  • PM10: 0.85 µg/m³
  • O3: 0.013 ppm
  • NO2: 1.5 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: 0.76 µg/m³
  • PM10: 0.8 µg/m³
  • O3: 0.013 ppm
  • NO2: 1.6 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: 0.65 µg/m³
  • PM10: 0.7 µg/m³
  • O3: 0.012 ppm
  • NO2: 1.6 ppb
  • SO2: 0 ppb
  • CO: 0.10 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: 0.65 µg/m³
  • PM10: 0.7 µg/m³
  • O3: 0.013 ppm
  • NO2: 1.1 ppb
  • SO2: 0 ppb
  • CO: 0.10 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.66 µg/m³
  • PM10: 0.81 µg/m³
  • O3: 0.025 ppm
  • NO2: 0.4 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
26 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.7 µg/m³
  • PM10: 0.94 µg/m³
  • O3: 0.028 ppm
  • NO2: 0.2 ppb
  • SO2: 0 ppb
  • CO: 0.08 ppm

Health Recommendations:

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

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

Pollutant Concentrations:

  • PM2.5: 0.73 µg/m³
  • PM10: 1.04 µg/m³
  • O3: 0.028 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: 0.7 µg/m³
  • PM10: 1.22 µg/m³
  • O3: 0.028 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.

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

Pollutant Concentrations:

  • PM2.5: 0.69 µg/m³
  • PM10: 1.31 µg/m³
  • O3: 0.028 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
26 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.72 µg/m³
  • PM10: 1.4 µg/m³
  • O3: 0.028 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: 0.77 µg/m³
  • PM10: 1.52 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: 0.84 µg/m³
  • PM10: 1.68 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
27 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.89 µg/m³
  • PM10: 1.9 µg/m³
  • O3: 0.029 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
26 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.93 µg/m³
  • PM10: 1.98 µg/m³
  • O3: 0.028 ppm
  • NO2: 0.3 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
24 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 0.97 µg/m³
  • PM10: 2 µg/m³
  • O3: 0.026 ppm
  • NO2: 0.5 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
23 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 1.01 µg/m³
  • PM10: 2.07 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.

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

Pollutant Concentrations:

  • PM2.5: 1.02 µg/m³
  • PM10: 2.05 µg/m³
  • O3: 0.022 ppm
  • NO2: 0.9 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: 1.04 µg/m³
  • PM10: 2.06 µg/m³
  • O3: 0.020 ppm
  • NO2: 1.1 ppb
  • SO2: 0 ppb
  • CO: 0.07 ppm

Health Recommendations:

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