The weather in Vancouver is unusually cold for this time of year, and nobody is feeling it more than the city's most vulnerable citizens.

Normal overnight lows for mid-November are around plus 2 degrees Celsius, but on Sunday the temperature is expected to drop to minus 7.

Kevin Lyons, 36, is staying at a Salvation Army shelter trying to face his demons and break his heroin addiction. He knows better than most how tough it is on the streets when it gets cold.

"I had been homeless in the winter. I broke into underground parking lots to stay warm," he said. "You're wet, you're cold, sick all the time. It's a nightmare."

He's one of 20 people who'll be staying at the shelter Sunday night, but hundreds more need a place to go.

Sean Spear is an associate director of RainCity Housing, which runs 11 transitional and long-term housing facilities in the city. He says workers at the filled-to-capacity Triage Shelter are opening up the TV room so people can get warm and escape the bitter outdoors.

"We never want to turn anyone away," he said. "There's 20-30 people we don't have space for."

Since an extreme weather alert was issued Thursday, shelters throughout Vancouver have been overflowing – and Environment Canada meteorologist Lisa Coldwells told CTV News it's only going to get colder in the days ahead.

"We're going to have a very brisk wind," she said. "That, combined with temperatures, is going to give a wind chill factor and it could feel as cold as minus 16.

Police have the authority to force people indoors under the Assistance to Shelter Act, but officials say that likely won't happen.

There are close to 2,000 shelter beds in Vancouver, and several extreme weather shelters that open in rotation when it gets this cold.

On Sunday night, St. Mark's at 1805 Larch Street in Kitsilano will be open, as will the Gathering Place at 609 Helmken Street downtown.

With a report from CTV British Columbia's Norma Reid