Madison Air Quality in April
Across 2019–2025, Madison's April air quality had a median AQI of 44 (Good) over 210 monitored days in the Madison, WI area. 0.0% of April days (0 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 57.6% of days. The cleanest April on record here was 2022 (median AQI 42, 0 days above 100) and the worst was 2023 (median 48, 0 days above 100, peak AQI 84).
- Good: 65.2%
- Moderate: 34.8%
- Unhealthy for Sensitive Groups: 0.0%
- Unhealthy or worse: 0.0%
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How is the air in Madison in April?
Good on a typical day: median AQI 44 across 2019–2025, with 0.0% of April days above AQI 100. Ground-level ozone is the main driver.
- ✓65.2% of April days were Good (AQI 0–50), 34.8% Moderate (51–100).
- ✓0 days of 210 reached AQI 101+; the April peak was 91.
- ✓Best April: 2022; worst April: 2023.
Frequently asked questions
What is the air quality like in Madison in April?▾
Across 2019–2025, the median daily AQI in Madison in April was 44 (Good). 65.2% of days were Good, 34.8% Moderate, and 0.0% reached Unhealthy for Sensitive Groups or worse, based on 210 monitored days in EPA's Air Quality System.
Is April a good time for outdoor exercise in Madison?▾
A typical April day in Madison sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.
Which pollutant causes Madison's April air quality problems?▾
Ground-level ozone set the daily AQI on 57.6% of April days in Madison. The highest April AQI recorded in 2019–2025 was 91 (Moderate), in 2023.
Madison April air quality, year by year
Madison April air quality by year (Madison, WI, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 45 | 0 | 73 | O3 |
| 2020 | 30 | 44 | 0 | 71 | PM2.5 |
| 2021 | 30 | 47 | 0 | 91 | PM2.5 |
| 2022cleanest | 30 | 42 | 0 | 60 | O3 |
| 2023worst | 30 | 48 | 0 | 84 | O3 |
| 2024 | 30 | 45 | 0 | 61 | O3 |
| 2025 | 30 | 44 | 0 | 63 | O3 |
What April air means in Madison
A typical April day in Madison sits in the Good range (median AQI 44), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of April days reached AQI 101+ in 2019–2025.
April's median AQI of 44 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 April AQI across every EPA metro area (100,677 metro-days, 2019–2025) is 44, so Madison runs in line with the national April norm; 0.0% of its April days topped AQI 100 versus 0.7% nationally (about the same).
April is part of Madison's spring season (March, April, May); the spring page pools all three months.
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 month 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.