Madison Air Quality in Summer
Across 2019–2025, Madison's summer (June–August) air quality had a median AQI of 47 (Good) over 644 monitored days in the Madison, WI area. 5.1% of summer days (33 of 644) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 50.8% of days. The cleanest summer on record here was 2019 (median AQI 43, 0 days above 100) and the worst was 2023 (median 63, 20 days above 100, peak AQI 268).
- Good: 55.1%
- Moderate: 39.8%
- Unhealthy for Sensitive Groups: 4.2%
- Unhealthy or worse: 0.9%
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How is the air in Madison in summer?
Good on a typical day: median AQI 47 across 2019–2025, with 5.1% of summer days above AQI 100. Ground-level ozone is the main driver.
- ✓55.1% of summer days were Good (AQI 0–50), 39.8% Moderate (51–100).
- ✓33 days of 644 reached AQI 101+; the summer peak was 268.
- ✓Cleanest month: August; worst month: June.
Frequently asked questions
What is the air quality like in Madison in summer?▾
Across 2019–2025, the median daily AQI in Madison in summer was 47 (Good). 55.1% of days were Good, 39.8% Moderate, and 5.1% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.
Is summer a good time for outdoor exercise in Madison?▾
A typical summer day in Madison sits in the Good range (median AQI 47), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 20 of summer days (5.1%) reached AQI 101+ in 2019–2025.
Which pollutant causes Madison's summer air quality problems?▾
Ground-level ozone set the daily AQI on 50.8% of summer days in Madison. The highest summer AQI recorded in 2019–2025 was 268 (Very Unhealthy), in 2023.
Madison summer air quality, year by year
Madison summer air quality by year (Madison, WI, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 92 | 43 | 0 | 93 | O3 |
| 2020 | 92 | 46 | 5 | 115 | O3 |
| 2021 | 92 | 55 | 1 | 101 | PM2.5 |
| 2022 | 92 | 45 | 0 | 84 | PM2.5 |
| 2023worst | 92 | 63 | 20 | 268 | PM2.5 |
| 2024 | 92 | 44 | 0 | 67 | O3 |
| 2025 | 92 | 53 | 7 | 170 | PM2.5 |
What summer air means in Madison
A typical summer day in Madison sits in the Good range (median AQI 47), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 20 of summer days (5.1%) reached AQI 101+ in 2019–2025.
Summer's median AQI of 47 is in line with Madison's whole-year median of 45, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median Summer AQI across every EPA metro area (308,645 metro-days, 2019–2025) is 46, so Madison runs in line with the national Summer norm; 5.1% of its Summer days topped AQI 100 versus 3.6% nationally (above average).
Within the season, August is the cleanest month (median AQI 44, 1.4% of days above 100) and June the worst (median 51, 11.4% 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.