Milwaukee Air Quality in 2023

In 2023, Milwaukee's air quality (Milwaukee-Waukesha-West Allis, WI area) had a median daily AQI of 53 (Moderate) across 365 monitored days. 28 days (7.7%) reached Unhealthy for Sensitive Groups or worse, 159 were Good, and the year's peak AQI was 270 (Very Unhealthy). Fine particulate matter (PM2.5) set the daily AQI on 245 of those days. The cleanest month of 2023 was November (median AQI 42, 0 days above 100) and the worst was June (median 97, 14 days above 100, peak 270).

53
Median AQI
Moderate
28
Days above AQI 100
7.7% of 365 days
93
90th percentile AQI
worst 1 day in 10
270
Peak AQI
Very Unhealthy
PM2.5
Main pollutant
245 of 365 days
159
Good days
43.6% of days
  • Good: 43.6%
  • Moderate: 48.8%
  • Unhealthy for Sensitive Groups: 6.6%
  • Unhealthy or worse: 1.1%

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QUICK ANSWER

How was Milwaukee's air quality in 2023?

Moderate on a typical day: median AQI 53, with 28 days above AQI 100 out of 365 monitored — the 7th cleanest of 7 years on record for the area.

  • Peak AQI in 2023: 270 (Very Unhealthy).
  • Fine particulate matter (PM2.5) was the main pollutant on 245 days.
  • Cleanest month: November; worst: June.

Frequently asked questions

What was the average AQI in Milwaukee in 2023?

EPA's Air Quality System puts Milwaukee's (Milwaukee-Waukesha-West Allis, WI) median daily AQI for 2023 at 53, which is Moderate. 28 days were Unhealthy for Sensitive Groups or worse and the year's highest AQI was 270.

Which month had the worst air quality in Milwaukee in 2023?

The cleanest month of 2023 was November (median AQI 42, 0 days above 100) and the worst was June (median 97, 14 days above 100, peak 270).

Was 2023 a good or bad year for Milwaukee'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 53 is above the area's typical annual median of 49.

Milwaukee month by month in 2023

Milwaukee air quality month by month, 2023 (Milwaukee-Waukesha-West Allis, WI, EPA AQS daily AQI)

MonthDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
January3157092PM2.5
February2848072PM2.5
March3152071PM2.5
April30501126O3
May31616126O3
Juneworst309714270PM2.5
July31613202O3
August31602136PM2.5
September3053090PM2.5
October31362108PM2.5
Novembercleanest3042091PM2.5
December3143081PM2.5

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 53 is above the area's typical annual median of 49.

Activity-specific thresholds: running, cycling, kids' sports.

Right now in Milwaukee

The latest EPA AirNow observation puts Milwaukee's AQI at 22 (PM2.5). The figures above are multi-year annual 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.