Update: Environment Canada lifted the fog advisory on Tuesday morning
Just two hours after lifting a fog advisory that was in effect for much of the day Monday, Environment Canada has issued another one.
The weather agency says fog will redevelop over southwestern Ontario Monday night and will stick around until Tuesday morning. Fog will become so dense in some spots it will reduce visibility to near zero.
Drivers are reminded to make sure their vehicle's full exterior lighting system is switched on so they are fully visible to other approaching vehicles.
Fog may not be the only threat to motorists. With the overnight temperature dropping to near freezing, untreated roads could also become icy.
A fog advisory was initially issued for London-Middlesex Sunday afternoon. It was ended nearly 24 hours later.
