The snow squall warning issued Thursday morning has since ended in the Barrie, Collingwood, and Hillsdale areas.
The cold conditions are a continuation of rough conditions from the day before.
Other areas impacted include Midland, Coldwater, Orr Lake, Orillia, Lagoon City, and Washago.
The national weather agency said additional snowfall amounts of around 5 cm are expected throughout the day.
Under the snow squall bands, the weather agency warns visibilities will be significantly reduced due to the heavy snow combined with blowing snow, and snow will quickly accumulate.
The snow squalls are expected to weaken later Thursday morning.