Denver Air Quality in June
Across 2019–2025, Denver's June air quality had a median AQI of 77 (Moderate) over 210 monitored days in the Denver-Aurora-Lakewood, CO area. 20.0% of June days (42 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 95.2% of days. The cleanest June on record here was 2025 (median AQI 74, 2 days above 100) and the worst was 2021 (median 87, 12 days above 100, peak AQI 172).
- Good: 9.5%
- Moderate: 70.5%
- Unhealthy for Sensitive Groups: 18.6%
- Unhealthy or worse: 1.4%
Reduce Indoor Ozone in Denver
Today's main pollutant in Denver is ground-level ozone (AQI 43). 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 Denver in June?
Moderate on a typical day: median AQI 77 across 2019–2025, with 20.0% of June days above AQI 100. Ground-level ozone is the main driver.
- ✓9.5% of June days were Good (AQI 0–50), 70.5% Moderate (51–100).
- ✓42 days of 210 reached AQI 101+; the June peak was 172.
- ✓Best June: 2025; worst June: 2021.
Frequently asked questions
What is the air quality like in Denver in June?▾
Across 2019–2025, the median daily AQI in Denver in June was 77 (Moderate). 9.5% of days were Good, 70.5% Moderate, and 20.0% 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 Denver?▾
A typical June day in Denver is Moderate (median AQI 77): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 5 of June days (20.0%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Denver's June air quality problems?▾
Ground-level ozone set the daily AQI on 95.2% of June days in Denver. The highest June AQI recorded in 2019–2025 was 172 (Unhealthy), in 2021.
Denver June air quality, year by year
Denver June air quality by year (Denver-Aurora-Lakewood, CO, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 74 | 3 | 115 | O3 |
| 2020 | 30 | 69 | 3 | 147 | O3 |
| 2021worst | 30 | 87 | 12 | 172 | O3 |
| 2022 | 30 | 76 | 9 | 169 | O3 |
| 2023 | 30 | 84 | 5 | 126 | O3 |
| 2024 | 30 | 84 | 8 | 143 | O3 |
| 2025cleanest | 30 | 74 | 2 | 108 | O3 |
What June air means in Denver
A typical June day in Denver is Moderate (median AQI 77): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 5 of June days (20.0%) 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 77 is above Denver's whole-year median of 64, 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 Denver runs above the national June norm; 20.0% of its June days topped AQI 100 versus 3.7% nationally (above average).
June is part of Denver's summer season (June, July, August); the summer page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Denver
The latest EPA AirNow observation puts Denver's AQI at 43 (O3). The figures above are multi-year month statistics, not today's reading.
View current Denver air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Denver-Aurora-Lakewood, 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.