CHICAGO, Ill. – Drivers across northern Illinois and northwest Indiana may encounter sudden visibility drops this morning as patchy dense fog settles over the region. The thickest fog is developing in river valleys, including stretches along the Kankakee, Illinois, and Iroquois rivers, where visibility can dip below half a mile through 9 a.m.
According to the National Weather Service in Chicago and Northern Indiana, the fog formed under clear skies and cooling overnight temperatures, with some localized pockets reducing visibility to just a quarter mile. Areas around Kankakee, Grundy, and Ford counties, as well as Lake, Porter, Newton, and Jasper counties in Indiana, are most at risk.
Motorists are urged to slow down, allow extra following distance, and use low-beam headlights in fog-prone areas. Expect the most abrupt visibility changes when traveling through low-lying terrain or near water.
The fog should lift by mid-morning as temperatures rise, but early commuters may face delays, especially on rural routes and near the rivers. No further advisories are expected after 9 a.m., but forecasters say patchy fog could redevelop in similar conditions later this week.
