Bundle up, Toronto.

Environment Canada has extended an extreme cold warning for the City of Toronto to Monday evening, as a bitter cold front covers the region.

Temperatures are expected to plummet to -24 C Sunday night, in the wake of a sharp arctic air mass. With wind chill, Environment Canada says it could feel as cold as -40 C outside.

The frigid wind chill is expected to continue during the Monday morning commute, lessen somewhat by the afternoon, and then drop back down to as low as -30 C Monday night.

“Stiff northwesterly winds combining with very cold, possibly record-setting minimum temperatures will once again result in extreme wind chills,” Environment Canada said in a statement.

People heading outdoors are urged to dress appropriately, as exposed skin may freeze in as little as 10 minutes.

Environment Canada is also warning that some people are at greater risk for frost bite and hypothermia, including homeless people and outdoor workers.