Toronto's uncharacteristically balmy winter is finally giving way to the harsh realities of the season.

A significant snowstorm on tap for the weekend will prove just the beginning of some difficult days ahead, where temperatures will drop to dangerous levels, feeling as cold as -19 C.

Meteorologists predict that southern Ontario is in for a serious deep freeze due to what is described as a "lake-effect snow squall event," pushing a surge of arctic air that could bring extreme cold conditions to Toronto lasting for more than five days.

The Weather Network shared an ominous window into the next week of winter weather in Toronto on Wednesday, warning that the upcoming band of weekend storms will give way to painfully frigid temperatures.

The trend of above-seasonal temperatures will come to a crashing halt on Sunday, when the mercury plummets to -6 C, with windchill factors making it feel like -14 C. Overnight on Sunday, the temperature will drop to a crisp -11 C.

Toronto residents will be shivering even more on Monday, with daytime temps reaching -8 C, feeling more like -15 C with windchill. Overnight, temperatures will once again drop further, reaching -14 C.

The worst of the cold snap is set to arrive on Tuesday, with daytime temperatures of -11 C, feeling as cold as -19 C. Overnight temps will remain in the negative double digits, leading into another frigid day on Wednesday, where temperatures of -9 C will feel more like -18 C.

For comparison, NASA's Perseverance rover's most recent readings, measured on January 5 from Mars' Jezero Crater, recorded daytime highs of -11 C – the same temperature expected for Toronto next Tuesday.

Areas further north in Ontario, like Thunder Bay, will see overnight lows dip to as cold as -25 C next week.