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.

Friday, July 26 - Thursday, August 1, 2024

Ozone

Good to USG levels.

Particle pollution (PM_2.5)

Good to Moderate 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)

High-pressure centered over the Great Lakes region Friday morning will slowly drift east today and Saturday, remaining the dominant meteorological feature during this period. Seasonable and mostly pleasant conditions are forecast today, but as the high-pressure system moves east and the southerly component to the flow becomes more robust, heat and humidity will drive heat indices well into the 90s from west-to-east Saturday into Sunday. Along with this increase in heat and moisture, precipitation chances will be on the rise for Sunday when scattered PM showers/storms are expected alongside breeze southerly flow. A mix of Good to Moderate AQI PM2.5 is forecast through the short-term period. On Friday, Moderate AQI PM2.5 is expected across western Wisconsin as elevated wildfire smoke mixes down to the surface. These conditions will then slowly spread east on Saturday and Sunday, with statewide Moderate AQI PM2.5 forecast on Sunday as any remnant smoke impacts will also be aided by increased humidity. We also expect to see a mix of Good to Moderate AQI ozone through this period, although USG AQI ozone can’t be ruled out on Saturday or Sunday. For Friday, the best chances for Moderate AQI ozone will be in south-central to southeast inland areas, but we’ll also acknowledge Moderate AQI ozone potential in western areas as the smoke impacts will have a chance to enhance ozone production. This will then set the stage for statewide Moderate AQI ozone potential Saturday and Sunday as the smoke impacts move east and the lake breeze comes into play. Currently, Saturday looks to hold the best chance for USG AQI ozone near Lake Michigan with stronger winds, increased cloud cover, and better chances for precipitation all suppressing ozone production potential on Sunday.

Extended Outlook (Days 4-7)

Precipitation chances look to continue Monday before a weak area of high-pressure moves in on Tuesday. This lull could be brief, however, as precipitation chances look to return both Wednesday and Thursday. USG AQI ozone near Lake Michigan cannot be completely ruled out for Monday as southerly flow, heat, and humidity will continue. As it stands now, cloud cover and precipitation look to keep ozone AQI in the Good to Moderate range. Mostly Good AQI is then expected Tuesday with some Moderate AQI potential lingering along Lake Michigan. Good AQI ozone is then forecast Wednesday before a mix of Good to Moderate AQI ozone returns Thursday. PM2.5 concentrations are currently expected to remain in the Good to Moderate AQI range, likely leaning more towards Good AQI. With that said, numerous wildfires are burning from northern California into Oregon, Washington, and southern British Columbia. For now, the flow pattern remains favorable, keeping the smoke to our north and west, but we’ll continue to monitor these and other fires throughout Canada as we approach the first week of August.

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].