Extreme cold weather warnings are in effect for Toronto and across southern Ontario this morning, as the city wakes up to record low temperatures in the –20s.

It was –25 C in Toronto when the sun came up on Saturday, but with the wind chill it felt like –40, cold enough to cause frostbite in just a few minutes. 

That's well below the city's the previous record low, –23.2, for this date, set in 1979.

An extreme cold weather alert issued earlier by the city remains in effect, as does a similar warning from Environment Canada. 

The weather agency says bitter north winds will keep the wind chill values between –30 and –40 through the morning, improving "only marginally" by afternoon. 

Temperatures will rise somewhat on Sunday, and will be closer to seasonal norms by Monday, according to forecasts. 

The city issues its alerts when temperatures are forecast to hit –15 or –20 with the wind chill.

Residents are encouraged to dress in warm layers and to call or visit friends, neighbours and family who might be having trouble with the cold weather. Infants and young children, the homeless, people who work outdoors and those with heart or respiratory illnesses are among those at risk, officials say. 

During such alerts extra effort is made to help homeless people to get off the street and into shelters. From Jan. 1 to Feb. 29, the city funds two drop-in centres that are open 24 hours.

If you see someone on the street who needs help with the cold call 311 or, for medical emergencies, 911.

The cold weather also prompted complaints from some basketball players and other celebrities — including rapper Snoop Dogg and the Miami Heat's Chris Bosh — who are in town for the NBA All-Star weekend.