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, September 10 - Tuesday, September 16, 2025

Ozone

Good (Green) to Moderate (Yellow) 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)

Updated Wednesday, September 10 - 11:10 AM

Generally calm conditions with isolated showers and associated cloud cover will continue across Wisconsin today. High temperatures in the low to mid 70s and Good (Green) AQI is expected, though Moderate (Yellow) AQI for ozone may be observed along the southern Lake Michigan shoreline. By tomorrow morning, influence from surface high pressure centered over northeastern Ontario will lead to light northeasterly flow over Wisconsin. Good AQI is forecast to continue. Flow will slowly shift to southeasterly throughout the day on Friday as low pressure develops in the northern Great Plains. Temperatures will warm a few degrees, reaching the mid to upper 70s. Chances for Moderate AQI ozone will increase along the lakeshore, with Good AQI more likely elsewhere. Unhealthy for Sensitive Groups (Orange) AQI ozone cannot be completely ruled out for locations that see a lake breeze. PM2.5 will remain in the Good to Moderate AQI range, with potential for minor impacts from ongoing burning across the southeastern U.S.

Extended Outlook (Days 4-7)

Conditions are looking to be rather consistent through the weekend and into early next week, as a large-scale upper-level blocking pattern is forecast to persist across the central U.S. As a result, southerly flow and a gradual warming trend are anticipated over Wisconsin. Long-range guidance suggests increased precipitation chances Friday night into Saturday morning as well as early next week. Good to Moderate AQI for both ozone and PM2.5 is forecast throughout the extended period, with chances for Moderate AQI ozone primarily along the lakeshore.

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].