Milwaukee Air Quality in August
Across 2019–2025, Milwaukee's August air quality had a median AQI of 51 (Moderate) over 217 monitored days in the Milwaukee-Waukesha-West Allis, WI area. 7.4% of August days (16 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 52.5% of days. The cleanest August on record here was 2019 (median AQI 42, 0 days above 100) and the worst was 2025 (median 45, 7 days above 100, peak AQI 160).
- Good: 49.3%
- Moderate: 43.3%
- Unhealthy for Sensitive Groups: 6.0%
- Unhealthy or worse: 1.4%
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How is the air in Milwaukee in August?
Moderate on a typical day: median AQI 51 across 2019–2025, with 7.4% of August days above AQI 100. Ground-level ozone is the main driver.
- ✓49.3% of August days were Good (AQI 0–50), 43.3% Moderate (51–100).
- ✓16 days of 217 reached AQI 101+; the August peak was 161.
- ✓Best August: 2019; worst August: 2025.
Frequently asked questions
What is the air quality like in Milwaukee in August?▾
Across 2019–2025, the median daily AQI in Milwaukee in August was 51 (Moderate). 49.3% of days were Good, 43.3% Moderate, and 7.4% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is August a good time for outdoor exercise in Milwaukee?▾
A typical August day in Milwaukee is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 14 of August days (7.4%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
Which pollutant causes Milwaukee's August air quality problems?▾
Ground-level ozone set the daily AQI on 52.5% of August days in Milwaukee. The highest August AQI recorded in 2019–2025 was 161 (Unhealthy), in 2025.
Milwaukee August air quality, year by year
Milwaukee August 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 |
|---|---|---|---|---|---|
| 2019cleanest | 31 | 42 | 0 | 67 | PM2.5 |
| 2020 | 31 | 48 | 0 | 90 | O3 |
| 2021 | 31 | 61 | 3 | 129 | PM2.5 |
| 2022 | 31 | 47 | 0 | 87 | O3 |
| 2023 | 31 | 60 | 2 | 136 | PM2.5 |
| 2024 | 31 | 52 | 4 | 161 | O3 |
| 2025worst | 31 | 45 | 7 | 160 | O3 |
What August air means in Milwaukee
A typical August day in Milwaukee is Moderate (median AQI 51): outdoor exercise is acceptable for most people, but unusually sensitive individuals should watch for symptoms, and about 1 day in 14 of August days (7.4%) reached AQI 101+ — the level at which EPA advises people with asthma, children and older adults to shorten hard outdoor exertion.
August's median AQI of 51 is in line with Milwaukee's whole-year median of 49, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median August AQI across every EPA metro area (104,152 metro-days, 2019–2025) is 45, so Milwaukee runs above the national August norm; 7.4% of its August days topped AQI 100 versus 3.5% nationally (above average).
August is part of Milwaukee's summer season (June, July, August); the summer 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 34 (PM2.5). 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.