UPDATE: Fog advisory ended for areas of southern Ontario
The fog advisory has ended for the city of Toronto, but does remain in effect for much of the GTA.
Niagara, Hamilton, Halton region, Dufferin and York-Durham region are still under a fog advisory.
Police are advising motorists to use extra caution on the roads in those areas.
Persistent fog with visibility near zero is expected.
The reduced visibility could make for poor driving conditions throughout much of the province.
Drivers are being advised to turn on the full headlights on their cars.
The Greater Toronto Airports Authority said that the fog was not causing any flight delays Sunday morning.
With files from Corinne Van Dusen