Madison Air Quality in Fall
Across 2019–2025, Madison's fall (September–November) air quality had a median AQI of 39 (Good) over 637 monitored days in the Madison, WI area. 0.0% of fall days (0 of 637) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 71.7% of days. The cleanest fall on record here was 2019 (median AQI 37, 0 days above 100) and the worst was 2022 (median 44, 0 days above 100, peak AQI 91).
- Good: 70.5%
- Moderate: 29.5%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Madison in fall?
Good on a typical day: median AQI 39 across 2019–2025, with 0.0% of fall days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓70.5% of fall days were Good (AQI 0–50), 29.5% Moderate (51–100).
- ✓0 days of 637 reached AQI 101+; the fall peak was 97.
- ✓Cleanest month: October; worst month: September.
Frequently asked questions
What is the air quality like in Madison in fall?▾
Across 2019–2025, the median daily AQI in Madison in fall was 39 (Good). 70.5% of days were Good, 29.5% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 637 monitored days in EPA's Air Quality System.
Is fall a good time for outdoor exercise in Madison?▾
A typical fall day in Madison sits in the Good range (median AQI 39), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of fall days reached AQI 101+ in 2019–2025.
Which pollutant causes Madison's fall air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 71.7% of fall days in Madison. The highest fall AQI recorded in 2019–2025 was 97 (Moderate), in 2022.
Madison fall air quality, year by year
Madison fall air quality by year (Madison, WI, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 91 | 37 | 0 | 81 | PM2.5 |
| 2020 | 91 | 39 | 0 | 66 | PM2.5 |
| 2021 | 91 | 42 | 0 | 75 | PM2.5 |
| 2022worst | 91 | 44 | 0 | 91 | PM2.5 |
| 2023 | 91 | 39 | 0 | 83 | PM2.5 |
| 2024 | 91 | 38 | 0 | 93 | PM2.5 |
| 2025 | 91 | 38 | 0 | 97 | PM2.5 |
What fall air means in Madison
A typical fall day in Madison sits in the Good range (median AQI 39), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of fall days reached AQI 101+ in 2019–2025.
Fall's median AQI of 39 is below Madison's whole-year median of 45, making it one of the area's cleaner periods. Nationally, the median Fall AQI across every EPA metro area (296,275 metro-days, 2019–2025) is 40, so Madison runs in line with the national Fall norm; 0.0% of its Fall days topped AQI 100 versus 1.5% nationally (below average).
Within the season, October is the cleanest month (median AQI 37, 0.0% of days above 100) and September the worst (median 42, 0.0% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Madison
The latest EPA AirNow observation puts Madison's AQI at 49 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current Madison air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Madison, WI), 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.