The weather system, which has paralyzed parts of the U.S. Midwest for the second time in a week, was making a slow eastward trek early Wednesday.
The departure board at Pearson was showing at least 106 cancelled flights through the late morning and at least 80 cancelled arrivals.
Most of the affected flights are to and from U.S. destinations coping with heavy, wet snow that has clogged roads and airports and blamed for at least three deaths.
The Toronto area received a heavy dose of rain and snow overnight and was expected to receive about five centimetres of additional snow throughout the day.
Areas north of the city received about 10 centimetres of snow during the night and Environment Canada said another five to 10 centimetres was likely Wednesday. Eastern Ontario was expected to receive about 15 centimetres by early Thursday.
Snowfall warnings have been posted for the Montreal region, with at least another 15 centimetres of snow in the forecast.
Travellers are urged to check their flight status before heading to the airports.