Environment Canada issued Monday morning a fog advisory for most parts of Southwestern Ontario
It includes London-Middlesex (Elgin), Oxford-Brant and Chatham-Kent as well Windsor-Essex.
Freezing fog can lead to near zero visibility in some areas, while untreated surfaces could become slippery and icy.
Motorists should slow down, be aware of tail lights ahead, and be ready to stop.
The fog should lift by this morning.