Police in the GTA are advising motorists to use extra caution as a thick blanket of fog makes driving tricky.

A fog advisory was issued by Environment Canada for the Greater Toronto Area and much of southern Ontario, Saturday afternoon. Persistent fog with visibility near zero is expected in some areas tonight through Sunday morning, the agency says.

The advisory covers an area stretching roughly from Goderich to Cornwall. The reduced visibility could make for poor driving conditions throughout much of the province.

“Travel is expected to be hazardous due to reduced visibility in some locations,” Environment Canada said in its statement. “If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop.”

A number of police services advised caution to motorists in social media posts, emphasizing full headlights and avoiding any distractions.

The Greater Toronto Airports Authority advised those travelling to their airport to be careful on the roads, but said that the fog was not causing any serious flight delays.

The fog comes along with a 40 per cent chance of drizzle in Toronto tonight and tomorrow.

Sunday is expected to be relatively warm in the city, with the temperature ranging between 4 C and 8 C.

Rain or snow is expected throughout much of next week, with the temperature expected to hover around the freezing mark.