Temperatures in Hamilton will fall rapidly Thursday night to reach lows of minus 20 to 25 degrees Celsius.
"A prolonged period of very cold wind chills is expected", warned Environment Canada.
The extreme cold is expected to continue until Sunday morning, when daytime highs are to return to the -10 range.
The reprieve from the deep freeze appears to be a brief one.
Federal Bureau of Investigation launches new probe into Clinton Foundation
The FBI is actively investigating the Clinton Foundation over corruption allegations, according to a report published Friday. He said Attorney General Jeff Sessions was doing President Trump's bidding to distract from the Russian Federation probe.
The cold isn't going anywhere - in fact it might get worse - and what's more, we're likely getting up to 10 more centimetres of snow this weekend and into Monday.
Unlike the recent cold snap, the Arctic blast in the forecast is expected to bring strong 50 km/h northwest winds, dropping the wind-chill values to between -35 to -40. Negative temperatures in the low 20s and wind chills as low as the mid-negative 30s will remain until Sunday morning.
And, of course, if it's too cold for people to be outside, it's also too cold for pets.
All city-run recreation centres are available during regular hours for those who need to stay warm and the MacNab Transit Terminal will stay open until HSR service ends.