Madison Air Quality in 2023
In 2023, Madison's air quality (Madison, WI area) had a median daily AQI of 51 (Moderate) across 365 monitored days. 25 days (6.8%) reached Unhealthy for Sensitive Groups or worse, 181 were Good, and the year's peak AQI was 268 (Very Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 250 of those days. The cleanest month of 2023 was October (median AQI 34, 0 days above 100) and the worst was June (median 110, 17 days above 100, peak 268).
- Good: 49.6%
- Moderate: 43.6%
- Unhealthy for Sensitive Groups: 5.5%
- Unhealthy or worse: 1.4%
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How was Madison's air quality in 2023?
Moderate on a typical day: median AQI 51, with 25 days above AQI 100 out of 365 monitored — the 7th cleanest of 7 years on record for the area.
- ✓Peak AQI in 2023: 268 (Very Unhealthy).
- ✓Fine particulate matter (PM2.5) was the main pollutant on 250 days.
- ✓Cleanest month: October; worst: June.
Frequently asked questions
What was the average AQI in Madison in 2023?▾
EPA's Air Quality System puts Madison's (Madison, WI) median daily AQI for 2023 at 51, which is Moderate. 25 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 268.
Which month had the worst air quality in Madison in 2023?▾
The cleanest month of 2023 was October (median AQI 34, 0 days above 100) and the worst was June (median 110, 17 days above 100, peak 268).
Was 2023 a good or bad year for Madison's air?▾
Among the 7 years EPA has published for the area (2019–2025), 2023 ranks 7th cleanest by days above AQI 100 — the worst year on record here. 2023's median of 51 is above the area's typical annual median of 45.
Madison month by month in 2023
Madison air quality month by month, 2023 (Madison, WI, EPA AQS daily AQI)
| Month | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| January | 31 | 52 | 0 | 88 | PM2.5 |
| February | 28 | 44 | 0 | 73 | PM2.5 |
| March | 31 | 47 | 0 | 75 | PM2.5 |
| April | 30 | 48 | 0 | 84 | O3 |
| May | 31 | 59 | 5 | 140 | O3 |
| Juneworst | 30 | 110 | 17 | 268 | PM2.5 |
| July | 31 | 54 | 3 | 154 | O3 |
| August | 31 | 58 | 0 | 76 | PM2.5 |
| September | 30 | 51 | 0 | 71 | PM2.5 |
| Octobercleanest | 31 | 34 | 0 | 71 | PM2.5 |
| November | 30 | 36 | 0 | 83 | PM2.5 |
| December | 31 | 43 | 0 | 78 | PM2.5 |
How 2023 compares
Among the 7 years EPA has published for the area (2019–2025), 2023 ranks 7th cleanest by days above AQI 100 — the worst year on record here.
2023's median of 51 is above the area's typical annual median of 45.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Madison
The latest EPA AirNow observation puts Madison's AQI at 24 (PM2.5). The figures above are multi-year annual 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.