With the wind chill, it felt like it was around -40 C in Regina on Monday. (Niall McKenna/CBC)

Saskatchewan's deep freeze, the weather system that seemed to come out of nowhere, is going to stick around for a while, weather forecasters say.

Throughout the south and central parts of the province, temperatures plummeted to well below -20 C on the weekend and are still there.

Wind chills make it feel like it's in the -40s.

Wind chill warnings were in effect in more than 45 communities on Monday morning.

The Prairie Valley School Division cancelled school bus service for the day and at least one of its schools, in Sedley, said it would be closed.

Officials with Environment Canada were saying they don't expect things to warm up much until after Christmas.

"Unfortunately, it's going to stay cold for the next several days in the Prairies as we get into a persistent arctic ridge of high pressure that's going to dominate," said James Cummine, a spokesman for the weather agency.

People need to be prepared, packing the necessary supplies and checking the highway hotline before travelling, Cummine said.

The frigid weather was no doubt on the minds of tens of thousands of people northwest of Saskatoon who lost power on Sunday.

Without power, furnaces shut down. Wind chills made it feel like -45 C outside.

According to SaskPower, a substation west of Martensville malfunctioned, triggering the outage, which started just before 5:30 p.m. and lasted two hours.

It affected roughly 10,000 homes and businesses in Martensville, Dalmeny, Osler, Langham, Rosthern, Borden, Hague, St. Benedict and Wakaw.

Meanwhile, groups that help homeless people were preparing for an influx on the weekend.

"A lot of people just want to remain anonymous and remain in the background," said Derrick Moore, who works at Soul Harbour Rescue Mission in Regina. "But when it's 45 below they don't have much choice. A lot of them have to step and say 'I need help.'"

Souls Harbour's emergency beds tend to be full on the coldest nights, but they'll always find ways to deal with the overflow, Moore said.

"If it's 30 below, we're not going to turn them away. And we can lead them to other resources, too, — Mobile Crisis and Salvation Army. We all kind of share and help each other when it's really, really cold like that."