Milwaukee Air Quality in April
Across 2019–2025, Milwaukee's April air quality had a median AQI of 45 (Good) over 210 monitored days in the Milwaukee-Waukesha-West Allis, WI area. 1.0% of April days (2 of 210) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 59.0% of days. The cleanest April on record here was 2022 (median AQI 44, 0 days above 100) and the worst was 2023 (median 50, 1 day above 100, peak AQI 126).
- Good: 61.9%
- Moderate: 37.1%
- Unhealthy for Sensitive Groups: 1.0%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Milwaukee
Today's main pollutant in Milwaukee is ground-level ozone (AQI 32). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in Milwaukee in April?
Good on a typical day: median AQI 45 across 2019–2025, with 1.0% of April days above AQI 100. Ground-level ozone is the main driver.
- ✓61.9% of April days were Good (AQI 0–50), 37.1% Moderate (51–100).
- ✓2 days of 210 reached AQI 101+; the April peak was 126.
- ✓Best April: 2022; worst April: 2023.
Frequently asked questions
What is the air quality like in Milwaukee in April?▾
Across 2019–2025, the median daily AQI in Milwaukee in April was 45 (Good). 61.9% of days were Good, 37.1% Moderate, and 1.0% 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 Milwaukee?▾
A typical April day in Milwaukee sits in the Good range (median AQI 45), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 100 of April days (1.0%) reached AQI 101+ in 2019–2025.
Which pollutant causes Milwaukee's April air quality problems?▾
Ground-level ozone set the daily AQI on 59.0% of April days in Milwaukee. The highest April AQI recorded in 2019–2025 was 126 (Unhealthy for Sensitive Groups), in 2023.
Milwaukee April air quality, year by year
Milwaukee April air quality by year (Milwaukee-Waukesha-West Allis, WI, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019 | 30 | 48 | 0 | 79 | O3 |
| 2020 | 30 | 50 | 0 | 70 | PM2.5 |
| 2021 | 30 | 48 | 1 | 109 | PM2.5 |
| 2022cleanest | 30 | 44 | 0 | 63 | O3 |
| 2023worst | 30 | 50 | 1 | 126 | O3 |
| 2024 | 30 | 44 | 0 | 67 | O3 |
| 2025 | 30 | 44 | 0 | 64 | O3 |
What April air means in Milwaukee
A typical April day in Milwaukee sits in the Good range (median AQI 45), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 100 of April days (1.0%) reached AQI 101+ in 2019–2025.
April's median AQI of 45 is below Milwaukee's whole-year median of 49, making it one of the area's cleaner periods. Nationally, the median April AQI across every EPA metro area (100,677 metro-days, 2019–2025) is 44, so Milwaukee runs in line with the national April norm; 1.0% of its April days topped AQI 100 versus 0.7% nationally (about the same).
April is part of Milwaukee's spring season (March, April, May); the spring page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Milwaukee
The latest EPA AirNow observation puts Milwaukee's AQI at 32 (O3). The figures above are multi-year month statistics, not today's reading.
View current Milwaukee air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Milwaukee-Waukesha-West Allis, 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.