Saskatchewan is back in a deep freeze.

Extreme cold warnings have expanded to include the entire province.

Environment Canada says a period of cold wind chills are continuing in the province’s north and that a fast-moving cold front will bring snow across southern Saskatchewan overnight Wednesday and into Thursday.

The cold front will bring extreme wind chills in the -40 to -45 range across the south, and areas in the north may see wind chill values reach as low as -50.

Conditions will begin to moderate over western Saskatchewan on Thursday night, according to Environment Canada.

The extreme cold warnings were first issued Tuesday across much of the province, with many areas seeing temperatures dip below -30 C and wind chills reach well below -40.

The weather agency warned early Wednesday a slight increase in temperatures would only be brief, with a return to the extreme cold by the end of the day and Thursday.

School buses were cancelled Wednesday in the south for the Regina Catholic School Division, the Regina Public School Division and for Balgonie, Bethune, Edenwold, Grand Coulee, Lumsden, Milestone, Pense, Pilot Butte, Regina, Regina Beach and White City in the Prairie Valley School Division.

In the north, all Prairie Spirit School Division buses were cancelled except Blaine Lake, Duke Lake and Leask. First Student Canada buses to St. Frances School and Cosmo Industries in Saskatoon were delayed, and all First Student wheel chair and rural routes were cancelled.