Department meteorologists use monitoring data and weather forecast models to predict Wisconsin's future ozone (O3) and fine particulate matter (PM2.5) air quality using the Air Quality Index (AQI) [exit DNR]. This forecast is updated two-to-three times weekly throughout the year, and when warranted, an Air Quality Advisory is issued. Below is the latest air quality forecast for Wisconsin.
Updated Monday, May 18 - 10:30 a.m.
Monday, May 18 - Sunday, May 24, 2026
Ozone
Good (Green) to Moderate (Yellow) AQI levels.
Particle pollution (PM2.5)
Good (Green) to Moderate (Yellow) AQI levels.
Short-Term Forecast Maps:
The black dots represent the approximate location of Wisconsin's air quality monitors. Read the forecast summaries below for further geographic information.
Short-Term Forecast (Days 1-3)
Despite southerly flow accompanied by above average temperatures, ozone production should be limited by cloud cover today (Monday), with most areas forecast for Good (Green) AQI on the day. We will maintain a Moderate (Yellow) AQI ozone and PM2.5 forecast for lakeshore areas. Precipitation chances will be on the increase through the p.m. hours, with widespread storms expected to roll through tonight into early Tuesday morning. Blustery northwest winds behind the cold frontal passage will lead to cooler temperatures and Good (Green) AQI on Tuesday, which will be maintained on Wednesday as high pressure drifts over the Great Lakes region.
Extended Outlook (Days 4-7)
Good AQI is currently expected to continue Thursday and Friday with a favorable NE flow over Lake Michigan helping to maintain at to slightly below normal high temperatures. Precipitation chances then look to be on the increase later Friday through the weekend. Assuming rain/clouds keep temperatures in check, Good AQI looks most likely, with a chance for Moderate AQI to develop if we see sunnier skies and warmer temperatures.
Air Quality Index (AQI) ranges
For more information about AQI ranges and colors, see the U.S. EPA's Air Quality Index (AQI) Basics [exit DNR].