Toronto issued an extreme cold weather alert as temperatures were set to drop to -15 C on Sunday night.
Environment Canada was calling for temperatures in the city to feel like -25 C with wind chill from gusts up to 50 kilometres per hour.
Hamilton, Ont., with a low of -15 C Sunday night, also issued a cold weather alert.
The cities issue the alerts when Environment Canada forecasts temperatures below -15 C, or a wind chill of -20.
With extreme cold weather on the way check on loved ones especially seniors & people with special needs.
Emergency Management (@TorontoOEM) January 03, 2016
In Toronto, the alert prompts extra care for people experiencing homelessness, and service providers focus their attention on getting people into shelter or street respite.
The city also opens 11 additional shelter spaces during the alerts.
Public health officials in both cities noted that cold weather has the greatest effect on the homeless, the elderly, young children and infants.
With files from National Post staff