Chicago, IL – Dense marine fog is expected to rapidly spread inland across the Chicago metro area Tuesday evening, bringing visibility below a quarter mile in key counties.
According to the US National Weather Service Chicago, the initial fog threat will affect Lake and Cook counties in Illinois, as well as parts of Lake County, Indiana. The dense fog, visible on satellite as a white/gray band over Lake Michigan, will likely drift inland swiftly after sunset, continuing to expand into early Wednesday morning.
Motorists in Evanston, Waukegan, Lake Zurich, and surrounding suburbs should expect drastically reduced visibility, especially during late evening and early morning commutes. Officials urge drivers to slow down, use low-beam headlights, and maintain extra distance between vehicles.
This type of marine fog is typical during seasonal transitions but can cause sudden hazards. The National Weather Service warns that the fog may spread beyond initial impact areas overnight, potentially affecting inland communities by dawn Wednesday.
Residents should monitor local alerts and consider delaying non-essential travel overnight. Fog is expected to begin dissipating after sunrise Wednesday, but isolated pockets of low visibility may linger into the mid-morning hours.
