The City of Toronto has issued an extreme cold weather alert ahead of frigid temperatures expected overnight Saturday and on Sunday.

The alerts are issued when temperatures are expected to fall to -15 C. Saturday’s overnight temperature is expected to fall to -12 C, feeling -20 C with the wind chill. Sunday’s forecast high is – 8 C, which will feel like – 15 C with the wind chill.

Check the full forecast here.

During an extreme cold weather alert, the city steps up its street outreach efforts to help homeless people find shelter. Extra shelter beds are opened up and TTC tokens are handed out to help the homeless get to a shelter.

Environment Canada also issued a special weather statement for Toronto, York, Durham, Peel and Halton regions on Saturday afternoon, warning of intensifying flurries.

“Local snowfall amounts near 5 cm are expected, and it is quite possible a locale or two may receive near 10 cm of snow by mid evening,” the statement said.

“Motorists should be prepared for sudden poor winter driving conditions from low visibility in bursts of heavy snow and accumulating snow on untreated roads.”

The weather has also caused delays at Pearson Airport.

Winter operations and snow clearing will continue into the night. Confirm your flight status before heading out. — Toronto Pearson (@TorontoPearson) February 17, 2013

Air Canada has also issued a travel alert for those heading in or out of Pearson.