Denver Air Quality in November
Across 2019–2025, Denver's November air quality had a median AQI of 53 (Moderate) over 210 monitored days in the Denver-Aurora-Lakewood, CO area. 0.0% of November days (0 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 34.8% of days. The cleanest November on record here was 2022 (median AQI 49, 0 days above 100) and the worst was 2019 (median 57, 0 days above 100, peak AQI 91).
- Good: 40.0%
- Moderate: 60.0%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Denver
Today's main pollutant in Denver is ground-level ozone (AQI 39). 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 November?
Moderate on a typical day: median AQI 53 across 2019–2025, with 0.0% of November days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓40.0% of November days were Good (AQI 0–50), 60.0% Moderate (51–100).
- ✓0 days of 210 reached AQI 101+; the November peak was 94.
- ✓Best November: 2022; worst November: 2019.
Frequently asked questions
What is the air quality like in Denver in November?▾
Across 2019–2025, the median daily AQI in Denver in November was 53 (Moderate). 40.0% of days were Good, 60.0% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is November a good time for outdoor exercise in Denver?▾
A typical November day in Denver is Moderate (median AQI 53): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of November days 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 November air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 34.8% of November days in Denver. The highest November AQI recorded in 2019–2025 was 94 (Moderate), in 2019.
Denver November air quality, year by year
Denver November air quality by year (Denver-Aurora-Lakewood, CO, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019worst | 30 | 57 | 0 | 91 | PM2.5 |
| 2020 | 30 | 53 | 0 | 77 | NO2 |
| 2021 | 30 | 52 | 0 | 90 | NO2 |
| 2022cleanest | 30 | 49 | 0 | 66 | PM2.5 |
| 2023 | 30 | 56 | 0 | 67 | O3 |
| 2024 | 30 | 52 | 0 | 94 | O3 |
| 2025 | 30 | 51 | 0 | 77 | O3 |
What November air means in Denver
A typical November day in Denver is Moderate (median AQI 53): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and fewer than 1% of November days reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
November's median AQI of 53 is below Denver's whole-year median of 64, making it one of the area's cleaner periods. Nationally, the median November AQI across every EPA metro area (92,704 metro-days, 2019–2025) is 39, so Denver runs above the national November norm; 0.0% of its November days topped AQI 100 versus 0.6% nationally (about the same).
November is part of Denver's fall season (September, October, November); the fall 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 39 (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.