January has brought Toronto back to reality with sub-zero temperatures and snowfall after an unseasonably warm December. It still feels like winter has yet to truly arrive in the city, though this streak of mild weather is about to end with a bang.

The new year kicked off with a return to below-freezing conditions, though an above-seasonal trend persists in Toronto, with highs in the low single digits expected for the next several days.

The city will get another taste of winter on Thursday when temps will feel as cold as -9 C with wind chill factors, but things could soon get much worse, as a shift of Arctic air is expected to push into Ontario in mid-January.

This year's mild temps are being attributed to a particularly strong El Niño, though a frigid Polar Vortex is threatening to cancel out El Niño's effects and bring frosty air to many parts of the country in the coming days.

This Arctic system is already taking hold in Yukon and the Northwest Territories after a similarly mild December for the northern territories, and this air is expected to spill over wide swathes of the country by next week.

Though the worst of this system is projected to miss Southern Ontario, there will indeed be a plunge in temperatures for Canada's largest city that will remind residents how brutal winters can get in this town.

The Weather Network predicts that the second and third weeks of the month "will feature a very active storm track from the Great Lakes to Atlantic Canada," warning of "the potential for the Arctic air to shift east into Ontario and Quebec for several days."

Snow is also in the cards for Toronto, though meteorologists are offering up a wide range on just how much may fall in the next two weeks.

The Weather Network's 14-day forecast calls for between 6 and 16 cm of the white stuff between Jan. 6 and Jan. 16, though pockets of sunshine and rain may prevent large accumulations of snow.

Despite bouts of frigid weather in the cards, much of the country — including Ontario — is expected to return to above-seasonal temperatures later in the month, a traditional "January thaw."

The Weather Network notes that while much of the country will remain at or above seasonal norms for January, "this is still a rather dramatic contrast to what we saw during December, especially since January is the coldest month of the year for most places, so normal is still very cold."