St. Louis Air Quality in November
Across 2019–2025, St. Louis's November air quality had a median AQI of 56 (Moderate) over 210 monitored days in the St. Louis, MO-IL area. 1.0% of November days (2 of 210) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 83.3% of days. The cleanest November on record here was 2024 (median AQI 44, 0 days above 100) and the worst was 2025 (median 59, 1 day above 100, peak AQI 109).
- Good: 25.7%
- Moderate: 73.3%
- Unhealthy for Sensitive Groups: 1.0%
- Unhealthy or worse: 0.0%
Extra Protection for St. Louis Homes
Air quality in St. Louis is moderate (AQI 60), 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.
Recommended: Coway AP-1512HH Mighty — True HEPA + carbon · CADR ~246 CFM · rooms up to 361 sq ft
As an Amazon Associate, we earn from qualifying purchases.
How is the air in St. Louis in November?
Moderate on a typical day: median AQI 56 across 2019–2025, with 1.0% of November days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓25.7% of November days were Good (AQI 0–50), 73.3% Moderate (51–100).
- ✓2 days of 210 reached AQI 101+; the November peak was 109.
- ✓Best November: 2024; worst November: 2025.
Frequently asked questions
What is the air quality like in St. Louis in November?▾
Across 2019–2025, the median daily AQI in St. Louis in November was 56 (Moderate). 25.7% of days were Good, 73.3% Moderate, and 1.0% 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 St. Louis?▾
A typical November day in St. Louis is Moderate (median AQI 56): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 100 of November days (1.0%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes St. Louis's November air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 83.3% of November days in St. Louis. The highest November AQI recorded in 2019–2025 was 109 (Unhealthy for Sensitive Groups), in 2025.
St. Louis November air quality, year by year
St. Louis November air quality by year (St. Louis, MO-IL, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 59 | 0 | 86 | PM2.5 |
| 2020 | 30 | 57 | 0 | 82 | PM2.5 |
| 2021 | 30 | 56 | 0 | 87 | PM2.5 |
| 2022 | 30 | 58 | 1 | 109 | PM2.5 |
| 2023 | 30 | 57 | 0 | 89 | PM2.5 |
| 2024cleanest | 30 | 44 | 0 | 58 | PM2.5 |
| 2025worst | 30 | 59 | 1 | 109 | PM2.5 |
What November air means in St. Louis
A typical November day in St. Louis is Moderate (median AQI 56): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 100 of November days (1.0%) 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 56 is in line with St. Louis's whole-year median of 58, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median November AQI across every EPA metro area (92,704 metro-days, 2019–2025) is 39, so St. Louis runs above the national November norm; 1.0% of its November days topped AQI 100 versus 0.6% nationally (about the same).
November is part of St. Louis's fall season (September, October, November); the fall page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in St. Louis
The latest EPA AirNow observation puts St. Louis's AQI at 60 (PM2.5). The figures above are multi-year month statistics, not today's reading.
View current St. Louis air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (St. Louis, MO-IL), 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.