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.

Wednesday, June 25 - Tuesday, July 1, 2025

Ozone

Good to Unhealthy AQI levels.

Particle pollution (PM_2.5)

Good to Moderate 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)

The boundary has sagged south of the state line overnight Tuesday into Wednesday morning, and along with mostly cloudy skies and scattered showers/storms, much of the state will see high temperatures range through the 60s-70s (areas to the southwest will likely reach the 80s) on Wednesday. Given the seasonably cool temperatures and wet and cloudy conditions, Good AQI is forecast statewide, but there is a chance for Low-Moderate ozone or PM2.5 to pop up on an isolated basis. Later today into Thursday, the boundary will lift north as a warm front associated with a more organized low pressure system that will move into the state throughout the day. Southerly flow south of the boundary has led to models predicting high ozone concentrations over southern Lake Michigan. Although ozone has struggled to form while we’ve been having high dew point temperatures, we’ll forecast USG AQI ozone for the southern portion of the Lake Michigan shoreline and even mention the potential for Unhealthy AQI ozone to form. Behind the system on Friday, westerly flow and partly to mostly cloudy skies are forecast before skies begin to gradually clear through the PM hours. The Good AQI PM2.5 forecast will continue with Moderate AQI ozone forecast for the southern lakeshore.

Extended Outlook (Days 4-7)

An area of weak of high pressure should help to keep things mostly dry for much of Saturday before upper-level disturbances bring storm chances late Saturday through Sunday. Models then show a front moving through the state NW to SE on Monday, potentially leading to more precipitation chances before cooler/drier air moves in from the NW. A pleasant and seasonable summer day is then forecast on Tuesday. Moderate AQI ozone potential will be in place Saturday and Sunday, along with a chance for USG AQI ozone along the lakeshore in the event of lake breeze. Otherwise, mostly Good AQI is forecast.

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].