Fort Collins Air Quality in June
Across 2019–2025, Fort Collins's June air quality had a median AQI of 64 (Moderate) over 210 monitored days in the Fort Collins, CO area. 9.1% of June days (19 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 97.1% of days. The cleanest June on record here was 2023 (median AQI 53, 0 days above 100) and the worst was 2021 (median 77, 7 days above 100, peak AQI 156).
- Good: 26.2%
- Moderate: 64.8%
- Unhealthy for Sensitive Groups: 8.6%
- Unhealthy or worse: 0.5%
Reduce Indoor Ozone in Fort Collins
Today's main pollutant in Fort Collins is ground-level ozone (AQI 36). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in Fort Collins in June?
Moderate on a typical day: median AQI 64 across 2019–2025, with 9.1% of June days above AQI 100. Ground-level ozone is the main driver.
- ✓26.2% of June days were Good (AQI 0–50), 64.8% Moderate (51–100).
- ✓19 days of 210 reached AQI 101+; the June peak was 156.
- ✓Best June: 2023; worst June: 2021.
Frequently asked questions
What is the air quality like in Fort Collins in June?▾
Across 2019–2025, the median daily AQI in Fort Collins in June was 64 (Moderate). 26.2% of days were Good, 64.8% Moderate, and 9.1% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is June a good time for outdoor exercise in Fort Collins?▾
A typical June day in Fort Collins is Moderate (median AQI 64): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 11 of June days (9.1%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Fort Collins's June air quality problems?▾
Ground-level ozone set the daily AQI on 97.1% of June days in Fort Collins. The highest June AQI recorded in 2019–2025 was 156 (Unhealthy), in 2021.
Fort Collins June air quality, year by year
Fort Collins June air quality by year (Fort Collins, CO, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 61 | 1 | 101 | O3 |
| 2020 | 30 | 60 | 1 | 108 | O3 |
| 2021worst | 30 | 77 | 7 | 156 | O3 |
| 2022 | 30 | 67 | 4 | 126 | O3 |
| 2023cleanest | 30 | 53 | 0 | 97 | O3 |
| 2024 | 30 | 67 | 2 | 112 | O3 |
| 2025 | 30 | 68 | 4 | 119 | O3 |
What June air means in Fort Collins
A typical June day in Fort Collins is Moderate (median AQI 64): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 11 of June days (9.1%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
June's median AQI of 64 is above Fort Collins's whole-year median of 51, making it one of the area's dirtier periods. Nationally, the median June AQI across every EPA metro area (100,635 metro-days, 2019–2025) is 46, so Fort Collins runs above the national June norm; 9.1% of its June days topped AQI 100 versus 3.7% nationally (above average).
June is part of Fort Collins's summer season (June, July, August); the summer page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Fort Collins
The latest EPA AirNow observation puts Fort Collins's AQI at 36 (O3). The figures above are multi-year month 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.