Most of Southern Ontario, including Waterloo Region, Guelph and Erin, is expected to see temperatures drop into the minus 20s over Sunday night and into Monday morning, with wind chill values in the minus 30s.
Environment Canada has issued a wind chill warning for those areas, saying temperatures will drop late Sunday night into Monday morning to - 26 C, with wind chill values hitting - 35.
The weather agency warns that in these conditions, frostbite and hypothermia can occur within minutes if appropriate precautions are not taken outdoors.
The wind chill warning comes after light snowfall overnight, with a 40 per cent chance of flurries midday Sunday. The high for Sunday is -11 C, well below seasonal values.
The average historical high for March 2 at 1 C.