A snow squall watch is in effect for parts of Simcoe County, and Muskoka on Monday has since ended.
The weather agency is expecting between 10 to 15 centimetres to fall by Monday afternoon.
The warning is in effect for Barrie, Orillia, Midland, Collingwood, Hillsdale, Coldwater, Orr Lake, Lagoon City, and Washago.
Residents are warned that visibility may be reduced due to blowing snow in some areas.
“Snow squalls cause weather conditions to vary considerably; changes from clear skies to heavy snow within just a few kilometres are common. Visibility will be suddenly reduced to near zero at times in heavy snow and blowing snow,” the weather agency said.
Environment Canada expects the squalls to taper off to flurries later in the afternoon.