Hourly Weather | Today Tuesday, June 30, 2026
Active Weather Warnings
Longmont, Colorado
4 PM
Sunny with a Chance of Thunderstorms
84°
Feels Like 86°
49
Humidity: 22%
UV Index: 5
Wind: 9 mph
5 PM
Cloudy Weather
84°
Feels Like 86°
17
Humidity: 22%
UV Index: 4
Wind: 9 mph
6 PM
Cloudy Weather
82°
Feels Like 82°
13
Humidity: 25%
UV Index: 2
Wind: 8 mph
7 PM
Cloudy Weather
82°
Feels Like 81°
17
Humidity: 28%
UV Index: 1
Wind: 8 mph
8 PM
Cloudy Weather
79°
Feels Like 75°
43
Humidity: 32%
UV Index: 0
Wind: 8 mph
9 PM
Cloudy Night
73°
Feels Like 72°
47
Humidity: 38%
UV Index: 0
Wind: 7 mph
10 PM
Stormy Weather
70°
Feels Like 64°
51
Humidity: 46%
UV Index: 0
Wind: 8 mph
11 PM
Cloudy Night
66°
Feels Like 64°
39
Humidity: 51%
UV Index: 0
Wind: 7 mph

Hourly Air Quality Forecast - AQI (US EPA)

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

Pollutant Concentrations:

  • PM2.5: 4.08 µg/m³
  • PM10: 5.02 µg/m³
  • O3: 0.042 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
41 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 5.91 µg/m³
  • PM10: 6.72 µg/m³
  • O3: 0.044 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
43 AQI
Good air quality Dominant pollutant: O3
Details

Pollutant Concentrations:

  • PM2.5: 9.25 µg/m³
  • PM10: 9.93 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.2 ppb
  • SO2: 0.1 ppb
  • CO: 0.09 ppm

Health Recommendations:

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

7 PM
52 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 13.08 µg/m³
  • PM10: 13.66 µg/m³
  • O3: 0.047 ppm
  • NO2: 0.3 ppb
  • SO2: 0.1 ppb
  • CO: 0.10 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

8 PM
60 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 16.51 µg/m³
  • PM10: 17.01 µg/m³
  • O3: 0.046 ppm
  • NO2: 0.5 ppb
  • SO2: 0.1 ppb
  • CO: 0.11 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

9 PM
67 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 19.85 µg/m³
  • PM10: 20.32 µg/m³
  • O3: 0.045 ppm
  • NO2: 0.7 ppb
  • SO2: 0.1 ppb
  • CO: 0.12 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

10 PM
71 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 21.84 µg/m³
  • PM10: 22.29 µg/m³
  • O3: 0.044 ppm
  • NO2: 0.7 ppb
  • SO2: 0.1 ppb
  • CO: 0.12 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

11 PM
74 AQI
Moderate air quality Dominant pollutant: PM2.5
Details

Pollutant Concentrations:

  • PM2.5: 23.44 µg/m³
  • PM10: 23.88 µg/m³
  • O3: 0.043 ppm
  • NO2: 0.8 ppb
  • SO2: 0.1 ppb
  • CO: 0.13 ppm

Health Recommendations:

Air quality is acceptable; some pollutants may pose a risk for a small number of unusually sensitive people.

Weather Alerts and Warnings for Longmont

Air Quality Alert

Air Quality Alert issued June 29 at 10:10PM MDT by NWS Denver CO
Jun 29, 10:10 PM Jun 30, 4:00 PM
The Colorado Department of Public Health and Environment has
issued the following...

WHAT...Action Day Alert for Multiple Pollutants.

WHERE...Douglas, Jefferson, Denver, western Arapahoe, western
Adams, Broomfield, Boulder, Larimer, and Weld Counties

WHEN...400 PM Monday June 29 to 400 PM Tuesday June 30

IMPACTS...Ozone Action Day Alert is now in effect for the Front
Range Urban Corridor. Hot, sunny, and occasionally smoky weather
conditions will result in ozone concentrations occasionally
reaching the Unhealthy for Sensitive Groups category on Monday and
Tuesday. Particle pollution levels could also reach the Unhealthy
for Sensitive Groups category, or worse, due to the wildfire
smoke. For Colorado air quality conditions, forecasts, and
advisories, visit:
https://www.colorado.gov/airquality/colorado_summary.aspx If
possible, please help us reduce ozone pollution by limiting
driving gas and diesel-powered vehicles until at least 4 p.m.
Tuesday, June 30, 2026. Colorado is also addressing ozone
pollution through state policies. For more information about
health impacts and how ozone pollution forms in Colorado, visit:
https://cdphe.colorado.gov/ozone- pollution-and-your-health

HEALTH INFORMATION...People with heart or lung disease, older
adults, and children should reduce prolonged or heavy exertion.
During periods of heavier wildfire smoke, everyone should reduce
prolonged or heavy exertion.
Updated: Jun 30, 3:12 PM Source: NWS Alert