Madison Air Quality in Spring

Across 2019–2025, Madison's spring (March–May) air quality had a median AQI of 44 (Good) over 644 monitored days in the Madison, WI area. 0.8% of spring days (5 of 644) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 52.0% of days. The cleanest spring on record here was 2025 (median AQI 41, 0 days above 100) and the worst was 2023 (median 51, 5 days above 100, peak AQI 140).

44
Median AQI
Good
0.8%
Days above AQI 100
5 of 644 days
61
90th percentile AQI
worst 1 day in 10
140
Peak AQI
Unhealthy for Sensitive Groups
PM2.5
Main pollutant
52.0% of days
65.2%
Good days
420 of 644
  • Good: 65.2%
  • Moderate: 34.0%
  • Unhealthy for Sensitive Groups: 0.8%
  • Unhealthy or worse: 0.0%

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QUICK ANSWER

How is the air in Madison in spring?

Good on a typical day: median AQI 44 across 2019–2025, with 0.8% of spring days above AQI 100. Fine particulate matter (PM2.5) is the main driver.

  • 65.2% of spring days were Good (AQI 0–50), 34.0% Moderate (51–100).
  • 5 days of 644 reached AQI 101+; the spring peak was 140.
  • Cleanest month: March; worst month: May.

Frequently asked questions

What is the air quality like in Madison in spring?

Across 2019–2025, the median daily AQI in Madison in spring was 44 (Good). 65.2% of days were Good, 34.0% Moderate, and 0.8% reached Unhealthy for Sensitive Groups or worse, based on 644 monitored days in EPA's Air Quality System.

Is spring a good time for outdoor exercise in Madison?

A typical spring 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 spring days reached AQI 101+ in 2019–2025.

Which pollutant causes Madison's spring air quality problems?

Fine particulate matter (PM2.5) set the daily AQI on 52.0% of spring days in Madison. The highest spring AQI recorded in 2019–2025 was 140 (Unhealthy for Sensitive Groups), in 2023.

Madison spring air quality, year by year

Madison spring air quality by year (Madison, WI, EPA AQS daily AQI)

YearDays monitoredMedian AQIDays above 100Peak AQIMain pollutant
20199244078PM2.5
20209244071PM2.5
20219248091PM2.5
20229242088PM2.5
2023worst92515140O3
20249243077O3
2025cleanest9241087O3

What spring air means in Madison

A typical spring 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 spring days reached AQI 101+ in 2019–2025.

Spring'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 Spring AQI across every EPA metro area (307,196 metro-days, 2019–2025) is 43, so Madison runs in line with the national Spring norm; 0.8% of its Spring days topped AQI 100 versus 0.8% nationally (about the same).

Within the season, March is the cleanest month (median AQI 42, 0.0% of days above 100) and May the worst (median 45, 2.3% 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.