Air Quality in Madison, Wisconsin — Live
Live readings from PurpleAir sensors across Madison — with free alerts the moment smoke drifts in.
AQI 56 from 5 PurpleAir sensors · Trending down · data from PurpleAir
As of , the air quality in Madison, Wisconsin is AQI 56 — Moderate and falling — with PM2.5 at 11.7 µg/m³, the median of 5 live PurpleAir sensors reading 32 to 62. Canairy's verdict: Mostly clear.
For scale, that PM2.5 reading is below the World Health Organization's 24-hour guideline of 15 µg/m³. The WHO figure is a daily average and this is a live reading, so read it as a sense of magnitude rather than a formal exceedance — a brief spike and a bad day are not the same thing. More on the WHO guidelines
Pollen today in Madison: weeds pollen is the strongest of the three at a high level, from Google's pollen forecast. Canairy shows the tree, grass and weed forecast beside the air reading on every plan, including the free one.
Free to download · Live data from PurpleAir & public monitors
Live PurpleAir sensor map for Madison and Middleton, Sun Prairie, Fitchburg, Verona. Every dot is a real sensor, color-coded by current air quality.
Sensor by sensor in Madison
The sensors Canairy reads in Madison are 30 AQI points apart right now, from Good to Moderate, which is the whole reason one city-wide number can mislead you: the median describes air you may not be standing in.
| From city center | AQI | Category |
|---|---|---|
| 1.5 mi WSW | 57 | Moderate |
| 3.2 mi ENE | 42 | Good |
| 3.3 mi NNE | 32 | Good |
| 4.5 mi W | 62 | Moderate |
| 5.4 mi SSW | 56 | Moderate |
Madison usually breathes easy. Sitting inland on its isthmus between Lake Mendota and Lake Monona, the city is well away from the Lake Michigan shoreline where most of Wisconsin's ozone trouble collects, and on a typical day its air lands in the Good range. What changes that picture is smoke from far away: in June 2023, Canadian wildfire haze settled over southern Wisconsin for days and turned the summer sky an eerie gray, a reminder that Madison's clean-air reputation depends partly on what the wind is carrying.
What Canairy does for Madison
A clear verdict
Not just a number — a plain-English call for Madison: open the windows, or keep them shut.
Smoke alerts
A push or text the moment the air crosses your threshold — and again when it clears.
A heads-up before it's bad
Trend alerts catch the air turning, so you can close up the house before the smoke settles in.
Every place you care about
Home, work, the kids' school — across Madison or across the country, on one screen.
What the air in Madison is doing next
| When | Expected air quality | Main pollutant |
|---|---|---|
| Today | Good | ozone |
| Tomorrow | Good | ozone |
| Monday | Good | ozone |
Forecast from EPA AirNow for the Madison Area reporting area. Canairy watches the live sensors against it and tells you when the air actually crosses your threshold, rather than leaving you to check.
The summer of 2023 was the worst smoke many locals remember
The Canadian wildfires of 2023 reached Wisconsin early and stayed on and off for weeks. Air quality alerts went up across the state as smoke first arrived around June 5 and 6, and through May and June the Upper Midwest recorded the highest ozone levels ever measured at a regional scale. For a region used to clean summer air, that was a genuinely unusual stretch.
The peak came on June 27, when a dense plume pushed south and gave Chicago, only about 90 miles from Madison, the worst air quality of any major city in the world at an AQI of 228. Southern Wisconsin sat under the same smoke, and Madison spent days with hazy skies and the kind of readings that make it worth keeping kids and anyone with asthma indoors. Smoke like that is not a yearly event here, but 2023 showed it can happen fast and with little warning.
Two lakes, a narrow isthmus, and hard winters
Madison's downtown is built on a thin strip of land between Lake Mendota and Lake Monona, part of the chain of lakes that shapes the whole city. That setting gives Madison its character, and it also means the weather can sit still. The climate is humid continental, with cold, calm high-pressure winters that reach 0 degrees F on roughly 17 mornings a year and drop about 51.8 inches of snow.
On those still, frigid winter days, the air near the ground does not move much, and whatever is in it, including smoke from wood-burning stoves and fireplaces, tends to settle rather than blow away. These episodes are usually short and local rather than the citywide events smoke brings, but they are the everyday version of air quality worth checking, especially in older neighborhoods where wood heat is common.
Inland, and away from Wisconsin's ozone belt
Most of Wisconsin's ozone problem hugs the Lake Michigan shoreline, where lake breezes trap pollution against the coast. The state's only ozone nonattainment areas are parts of Kenosha, Milwaukee County, and part of Sheboygan County, all on the eastern edge. Madison and the rest of Dane County sit inland and are not on that list, and statewide ozone has fallen significantly over the past few decades.
That is why, smoke aside, Madison's air usually reads Good. A representative check put the city at an AQI of 40 with fine-particle levels around 7.3 micrograms per cubic meter, pulled from roughly 17 local monitoring stations. The day-to-day story here is not chronic pollution; it is knowing which days, whether a smoke plume or a still winter morning, are the exceptions.
Madison air quality FAQ
What is the air quality in Madison right now?
As of September 5, 2026 at 9:40 AM CDT, the air quality in Madison, Wisconsin is AQI 56 — Moderate — with PM2.5 at 11.7 µg/m³, the median of 5 live PurpleAir sensors. Sensitive groups may want to take it slower outside.
Does wildfire smoke reach Madison?
Yes, though not every year. In June 2023, smoke from Canadian wildfires drifted over southern Wisconsin for days; air quality alerts went up across the state, and on June 27 the same plume gave nearby Chicago the worst air quality of any major city in the world. When smoke arrives it can push Madison's air from Good to unhealthy within hours, which is exactly the kind of change Canairy is built to warn you about.
Is Madison's air usually clean?
On a normal day, yes. Madison sits inland, away from the Lake Michigan shoreline where most of Wisconsin's ozone collects, and it typically reads in the Good range. The readings worth watching for are the exceptions: summer wildfire smoke and, in winter, wood smoke that settles on cold, still days.
What the AQI numbers mean
| AQI | Category | What it means for you |
|---|---|---|
| 0–50 | Good | Open the windows. Great for outdoor activity. |
| 51–100 | Moderate | Sensitive groups may want to take it slower outside. |
| 101–150 | Unhealthy for Sensitive Groups | Kids, elderly, and respiratory conditions stay closer to home. |
| 151–200 | Unhealthy | Skip outdoor exercise. Close windows. |
| 201–300 | Very Unhealthy | Limit time outside. N95 if you must go. |
| 301+ | Hazardous | Health emergency. Stay inside, run filtration if you have it. |
Canairy lets you tighten these bands if you’re more sensitive than the EPA default, so an alert can fire before the official category changes. How to read the Air Quality Index
Where these readings come from
The AQI at the top of this page is the median of the 5 curated PurpleAir sensors Canairy tracks in and around Madison, with outliers set aside so that one sensor brought indoors — or parked beside a barbecue — cannot set the number for a whole city. Every sensor behind it is listed above with its distance and bearing from the city center. There is no black box here.
In the app, a place you save resolves the same way first. When no neighborhood sensor is reporting it falls back to the nearest EPA AirNow monitor, and anything modeled rather than measured is labelled a regional estimate rather than passed off as a sensor reading. How low-cost sensors compare to regulatory monitors
About Canairy
Canairy is free to download. The free plan covers one saved place with live readings, a plain-English verdict, and push alerts when the air crosses a threshold you choose. Paid plans add more places, faster refreshes, and SMS alerts. It is built by two parents in Sonoma County, California, who got tired of guessing whether it was safe to send the kids outside. Why we built it
Go deeper
Air quality near Madison
We watch Madison's air. You live your life.
Set your threshold once and get a heads-up only when the air actually changes for you. Free on the App Store & Google Play.