All of Saskatchewan remains under an extreme cold warning as Environment and Climate Change Canada (ECCC) estimates temperatures as low as minus 50 in some parts of the province.

On their website, ECCC said that “extreme cold puts everyone at risk.”

“Risks are greater for young children, older adults, people with chronic illnesses, people working or exercising outdoors, and those without proper shelter,” ECCC said.

In Regina and Saskatoon, all transit to schools was cancelled for Monday, due to the extreme cold.

If wind chill is at –40C or lower at 6 am, transportation for students requiring vehicles equipped with lifts (for wheelchairs) will be cancelled. All student transportation is cancelled at –45C windchill at 6 am. Schools remain open, unless otherwise announced.

— Regina Public Schools (@RegPublicSchool) February 5, 2021

RECORDS SET, TIED

Here is a list of weather records that were broken and tied on Sunday. Note that these are intial findings from ECCC, and not its final report.

Buffalo Narrows

  • New record: -46.4
  • Cold Record: -40, 1962
  • Records kept since 1962

Collins Bay

  • New record: -43.4
  • Old record: -42.6, 1983
  • Records kept since 1972

Key Lake

  • New record: -48.7
  • Old record: -46.5, 2019
  • Records kept since 1976

Stony Rapids

  • New record: -47.6
  • Old record: -46.9, 1962
  • Records kept since 1960

Uranium City

  • New record: -48.9
  • Old record: -40, 2019
  • Records kept since 1966

Environment Canada meteorologist Terri Lang told CTVNews.ca on Monday that the record-breaking cold has been brought on by a polar vortex moving across western Canada, causing some regions to feel as cold as -50 with the wind chill.

"The spinning up of the cold air up around the North Pole… deepens and strengthens in the winter because of the lack of sunshine," Lang said in a telephone interview.

Lang explained that polar vortexes are not unusual, and their remnants push into Canada most winters around this time.

She said a polar vortex contains Arctic air that sits over the poles for much of the winter. When those weather systems break down heading into spring, Lang said, that Arctic air then falls into Canada.

"Across [the] Prairies, we're just getting some of that cold air that's coming down because the jet stream has looped far enough south. This is what happens every winter, and it’s what gives Canada its cold weather," Lang said.

In Uranium City a record was tied on Sunday morning, with minus 48.9 degrees.

“This same temperature has been recorded there once before, on January 15, 1974.” ECCC Weather Saskatchchewan said on Twitter.

It's a cold day out there!

In fact, Uranium City, in far northern Saskatchewan, tied an all-time cold record this morning, at a bone-chilling -48.9 degrees.

This same temperature has been recorded there once before, on January 15, 1974. #skstorm #skwx #cold

— ECCC Weather Saskatchewan (@ECCCWeatherSK) February 7, 2021

“At temps this cold, frostbite can happen in minutes, watch for signs of cold injury,” ECCC Weather Saskatchewan said.

Coldest temps of winter so far, for much of SK are forecast this weekend and early next week. #skstorm

Regina and Saskatoon will see temps between -35°C and -40°C by Mon, Feb 8 morning.

At temps this cold, frostbite can happen in minutes, watch for signs of cold injury. pic.twitter.com/Vn4gPz3sBF

— ECCC Weather Saskatchewan (@ECCCWeatherSK) February 5, 2021

“Canada just recorded its coldest temperature since 2017, thanks to the #polarvortex,” The Weather Network wrote on Twitter.

What's the coldest temperature you've ever experienced? Canada just recorded its coldest temperature since 2017, thanks to the #polarvortex.

Photo: Patsy Larocque

— The Weather Network (@weathernetwork) February 8, 2021

In some parts of Saskatchewan, it was cold enough to turn hot water to vapour. A trick shared far and wide on social media over recent winters.

Experiment to turn boiling water in snow in extreme weather -45 and more feels like in #yqr #yqrwx #skweather #Canada pic.twitter.com/L7GOwAW6MP

— Falak Naz (@nazalteejani) February 6, 2021

With files from CTVNews.ca's Brooklyn Neustaeter.