Department meteorologists use monitoring data and weather forecast models to predict Wisconsin's future ozone (O₃) and fine particulate matter (PM_2.5) 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 Thursday, December 18 - 10:45 AM

Thursday, December 18 - Wednesday, December 24, 2025

Ozone

Good (Green) AQI levels.

Particle pollution (PM_2.5)

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)

Southerly flow has maintained elevated PM2.5 concentrations on Thursday morning, but a strong cold front is approaching from the west and PM2.5 concentrations are expected to drop quickly behind it. Because of this, Moderate (Yellow) AQI PM2.5 will be possible for eastern areas today, with Good (Green) AQI further west. Frigid conditions are then anticipated to develop as strong northwest winds move in tonight into Friday morning. The cold will be short-lived however, as southerly flow makes a brief return on Saturday as another low moves across the northern Great Lakes. With an active pattern expected, Good (Green) AQI is forecast Friday and Saturday.

Extended Outlook (Days 4-7)

Favorable northwest flow should maintain Good AQI over the weekend before southerly flow develops later Sunday into Monday. This will lead to Moderate AQI PM2.5 chances for Monday and Tuesday. We’ll then see a chance for improving air quality on Wednesday as high pressure moves towards the Great Lakes region.

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].