Clear skies over Milwaukee this week are giving a misleading picture of local air conditions.
On June 3, the area’s first air quality alert of 2026 was issued after an uncommon weather setup kept ozone concentrated near the surface rather than allowing it to lift higher into the atmosphere.
What’s happening?
The alert from the National Weather Service was not driven by Canadian wildfire smoke, which has not yet reached levels strong enough to spread across the Midwest.
Instead, forecasters pointed to ozone. Benjamin Sheppard, a meteorologist with the National Weather Service, said a subsidence inversion pattern, a layer of warm, sluggish air, was preventing that pollution from dispersing upward, the Milwaukee Journal Sentinel reported…