The Baltimore region is under a dense fog advisory through 9 a.m. Wednesday.
Visibility will be low for motorists during the morning rush, and the National Weather Service warns that visibility may be reduced to a quarter of a mile at times.
The service says conditions may rapidly change, and that drivers should use low-beam headlights and leave plenty of distance between vehicles.
The advisory covers all of the Baltimore area, including the city and county, as well as Anne Arundel, Carroll, Harford, and Howard counties. Southern and western Maryland will see fog, as well, the advisory said.
Temperatures should touch the low 50s Wednesday before falling back to the 40s in the evening.