Your local guide
Regional air-quality reports for Fort Collins, with times and source links.
AIRNOW · FORT COLLINS REPORTING AREA (REGIONAL OBSERVATION)
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Regional observations from AirNow and the linked official reporting source. This is an area report, not a monitor on your street.
Check a local allergy forecast for pollen levels. Air quality and pollen measure different things.
Days with good air
43%
156 of 366 days
Median AQI
54
Moderate
Unhealthy-for-sensitive days or worse
23
Main pollutant
Ozone
300 days
Worst reading
AQI 161
Unhealthy
Average daily AQI for each month, 2022–2024. November is usually the cleanest month and July the worst.
Bars show days each year at “unhealthy for sensitive groups” (AQI above 100) or worse.
Ozone forms on hot, sunny afternoons, so it peaks in summer; plan runs and outdoor play for the morning on high-ozone days. Fine particles (PM2.5) come from wildfire smoke, traffic and wood burning and can spike in any season. Above 100, people with asthma, heart or lung conditions, older adults and children should limit long or heavy exertion outdoors.
In 2024, 43% of days had good air (AQI 50 or below) at Larimer County monitors, 51% were moderate and 23 days reached unhealthy for sensitive groups or worse. The median AQI was 54.
From 2022 to 2024, July had the highest average AQI (77) and November the lowest (47).
ozone (smog) was the main pollutant on 300 of 366 days in 2024.
The median AQI was 51 in 2015 and 54 in 2024; days at unhealthy for sensitive groups or worse went from 17 to 23.
Source: U.S. EPA AirData, annual and daily AQI by county, Larimer County, Colorado. County figures use the highest reading among the county’s monitors each day.
Air quality can vary within the reporting area. Use AirNow’s guidance and current reports when planning outdoor activity.
Open AirNow →Check weather and wind alongside the AQI. Pollen is a separate measurement and is not connected yet.
Local weather →Hours and availability change, so check with each place before you go.