Today | Weather | Sunday, September 21, 2025

Weather in Longmont, Colorado

09:54 PM
Now
Cloudy Night
64° F
Feels Like 63°
Precipitation 34 %
Wind 6 mph
Humidity 51 %
Today
Cloudy Night
Day 82°
Night 52°
Precipitation 49 %
Wind 10

Longmont Weather Forecast Updated

53 minutes ago
Last updated on

Air quality in Longmont

NOW
38 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 6.33 µg/m³
PM10 7.31 µg/m³
O₃ 22.95 ppb
NO₂ 11.71 ppb
SO₂ 0.36 ppb
CO 182.66 ppb
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide

Health Recommendations:

With this level of air quality, you have no limitations. Enjoy the outdoors