Dense fog that motorists contended with during Tuesday morning's commute is expected to return Wednesday and Thursday.
Environment Canada said dense fog was reported from Windsor to Georgian Bay, and at times was reducing visibility to 200 metres or less.
Airlines issue travel advisories
Because of the fog, Porter Airlines urged its customers to check their flight status before heading to the airport.
The airline issued a weather advisory for Toronto, Sudbury and Windsor airports.
In its own advisory, Air Canada said morning flights were threatened by "forecasted low ceilings, fog and reduced visibility and subsequent air traffic control restrictions."
As for the rest of the forecast, Environment Canada is predicting a high of 10 C in Toronto on Tuesday, with mainly cloudy skies.
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