After a stretch of unseasonably warm temperatures, a biting windchill has prompted Toronto's Medical Officer of Health, Dr. Eileen de Villa, to issue an extreme cold weather alert for the city of Toronto. 

According to the city, the alert is based on Environment and Climate Change Canada's forecast, which is calling for a windchill of -18 later this evening. 

An #ExtremeColdWeatherAlert has been issued for Toronto today. More info here: https://t.co/SzXX3p55qw

— Toronto Public Health (@TOPublicHealth) January 29, 2020

The cold snap will last until tomorrow, making temperatures feel like -15 in the morning on Thursday according to Environment Canada. 

The extreme cold weather alert will be in effect until further notice, and will activate local services that focus on getting vulnerable residents inside.

A warming centre will open at Metro Hall by 7 p.m. today, and will remain open continuously until noon on the day an alert is terminated.

This is Toronto's third extreme old weather alert this month.