A fog advisory for Sarnia-Lambton ended late Wednesday morning.
There was widespread fog across the region with reports of zero visibility.
Environment Canada said with temperatures near or just below the freezing mark, the fog may also deposited ice on untreated surfaces, resulting in slippery conditions on area roads and sidewalks.
The national weather agency said in foggy conditions, motorists are advised to slow down if visibility is reduced, watch for tail lights ahead and be prepared to stop.
