Fort Collins Air Quality in 2020
In 2020, Fort Collins's air quality (Fort Collins, CO area) had a median daily AQI of 49 (Good) across 366 monitored days. 22 days (6.0%) reached Unhealthy for Sensitive Groups or worse, 197 were Good, and the year's peak AQI was 159 (Unhealthy). Ground-level ozone set the daily AQI on 291 of those days. The cleanest month of 2020 was January (median AQI 44, 0 days above 100) and the worst was October (median 57, 8 days above 100, peak 159).
- Good: 53.8%
- Moderate: 40.2%
- Unhealthy for Sensitive Groups: 5.5%
- Unhealthy or worse: 0.5%
Extra Protection for Fort Collins Homes
Air quality in Fort Collins is moderate (AQI 51), with fine particles (PM2.5) the main concern. A True-HEPA purifier gives sensitive groups — kids, seniors and anyone with asthma or allergies — cleaner air indoors on days like today.
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How was Fort Collins's air quality in 2020?
Good on a typical day: median AQI 49, with 22 days above AQI 100 out of 366 monitored — the 5th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2020: 159 (Unhealthy).
- ✓Ground-level ozone was the main pollutant on 291 days.
- ✓Cleanest month: January; worst: October.
Frequently asked questions
What was the average AQI in Fort Collins in 2020?▾
EPA's Air Quality System puts Fort Collins's (Fort Collins, CO) median daily AQI for 2020 at 49, which is Good. 22 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 159.
Which month had the worst air quality in Fort Collins in 2020?▾
The cleanest month of 2020 was January (median AQI 44, 0 days above 100) and the worst was October (median 57, 8 days above 100, peak 159).
Was 2020 a good or bad year for Fort Collins's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 5th cleanest by days above AQI 100. 2020's median of 49 is in line with the area's typical annual median of 51.
Fort Collins month by month in 2020
Fort Collins air quality month by month, 2020 (Fort Collins, CO, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| Januarycleanest | 31 | 44 | 0 | 51 | O3 |
| February | 29 | 45 | 0 | 61 | O3 |
| March | 31 | 47 | 0 | 58 | O3 |
| April | 30 | 49 | 1 | 115 | O3 |
| May | 31 | 52 | 1 | 133 | O3 |
| June | 30 | 60 | 1 | 108 | O3 |
| July | 31 | 58 | 2 | 105 | O3 |
| August | 31 | 77 | 6 | 146 | O3 |
| September | 30 | 73 | 3 | 133 | PM2.5 |
| Octoberworst | 31 | 57 | 8 | 159 | PM2.5 |
| November | 30 | 45 | 0 | 59 | O3 |
| December | 31 | 44 | 0 | 57 | O3 |
How 2020 compares
Among the 7 years EPA has published for the area (2019–2025), 2020 ranks 5th cleanest by days above AQI 100.
2020's median of 49 is in line with the area's typical annual median of 51.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Fort Collins
The latest EPA AirNow observation puts Fort Collins's AQI at 51 (PM2.5). The figures above are multi-year annual statistics, not today's reading.
View current Fort Collins air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Fort Collins, CO), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.