Environment Canada calls for a high of minus 12 with a 60 per cent chance of flurries in Hamilton. The westerly winds will gust from 30 km/h to 50 km/h.

The overnight low will be minus 15. Wednesday will be mainly cloudy with a 40 percent chance of flurries in the afternoon and evening.

The Medical Officer of Health for the City of Hamilton issued a Cold Weather Alert on the morning of Jan. 18., as the temperature fell to around –8 C and felt like –16 C with the windchill.

Cold weather alerts are issued when weather conditions reach or dip below –15 C or –20 C with the wind chill — or if the temperature is expected to reach this point throughout the day.

David Phillips, senior climatologist with Environment Canada, said we should expect the cold weather to last, with the worst chills arriving early this week.

"It will begin in earnest on Monday with Tuesday the coldest, and maybe some warm up by the weekend," he said, adding temperatures could dip up to 10 degrees lower than average for this time of year.

He added the chill may feel particularly gruesome because we've enjoyed above average temperatures for so long.

"We've been seduced by one of the longest January thaws on record and this is something we haven't seen in two years. What we're going to see is really just winter," he said.

"We've gone through half the winter with nothing to complain about. This is Canada. We are the second-coldest country in the world and this is the winter season we're known for."

While temperatures might warm up next weekend, Phillips said not to stash the boots away just yet, as we could see several more thaws and chills before spring.

People in need of shelter are at particular risk during a cold weather alert, according to the Salvation Army, and they're asking the public to call 905-527-1444 ext. 0 if you see someone in need of shelter.

The Salvation Army is doing its best to make sure everyone is off the streets, said spokesperson Gary Brown.

Hamilton police officers help them go out and urge people inside, he said. Through the organization's Booth Centre, Salvation Army staff keep track of available shelter beds so they can match homeless people with available spaces.

Every once in a while, they encounter people who don't want to come in, he said.

"Sometimes it's not a lack of accommodation. It's someone's own choice to stay on the street," he said. "The shelter system will do everything they can to accommodate individuals. We want to make sure people are in out of the cold."

CBC News meteorologist and Hamiltonian, Jay Scotland says much of the country will face potentially dangerous wind chill values.

How cold is it? Let us know. Send us your cold weather pictures and stories and we'll post them here. Submit pictures using Twitter and the hashtag #HamOntCBCPics or send your pictures and/or stories in by email to hamilton@cbc.ca

Blizzard and snowfall warnings were in effect along the west coast of Newfoundland and southeastern Nova Scotia, where drivers were warned to give themselves ample time to reach morning destinations due to blowing snow and poor visibility. Southeastern Newfoundland looks likely to be the hardest hit by the storm, Scotland said, with about 15 centimetres expected to fall around the vicinity of St. John's and the Avalon.