Staff at homeless shelters in the Twin Cities likely will be working round-the-clock shifts by this weekend, when temperatures in the Twin Cities will bottom out in the double digits below zero.

The worst will come Saturday, when the high temperature is forecast to be 6 below. Before that, though, there’s a brief respite. Remember, warm is relative. Wednesday’s high is expected to be 6 degrees above zero; Thursday’s forecast called for 15 and Friday for 3. New Year’s Eve and New Year’s Day, well, 0 and 1 degree.

So, how do people who have to be outside, either by necessity or circumstance, deal with the cold?

Mail carriers will indeed deliver mail at temperatures of 15 below, said Darla Swanson, communications manager for the U.S. Postal Service. The carriers’ employer reminds them regularly to dress properly, stay dry, keep extra clothing in the vehicle in case they become wet and know the signs and symptoms of cold stress.

The same “safety first” credo applies for workers who are out battling ice buildup on the roads or cutting brush in the extreme cold, said Kevin Gutknecht, communications director for the Minnesota Department of Transportation (MnDOT).

Crews were working in various locations for MnDOT on Tuesday, Gutknecht said.

Outdoor work in the winter takes longer. That’s just the way it is, and MnDOT is OK with that, he said. Most outdoor work crews are experienced and know when it’s time to take a break to warm up.

“We want to make sure whatever we do, we want to do it safely,” Gutknecht said.

It’s not so easy for people who find themselves homeless in below-zero temperatures.

“Our practice is to try to stay open all day when the temperature is not going to creep above zero,” said Wendy Wiegmann, director of programs at Simpson Housing, which coordinates beds at several shelters in the metro area.

Most shelters close at 9 a.m. and reopen at 5 p.m., but that isn’t realistic when people need a place to be out of the dangerous cold and wind.

“It is definitely taxing to find the staffing, food, resources to keep operating when we normally close,” Wiegmann said. “We managed to stay up all day [Monday] and [Tuesday] for those that are staying at our shelter already.”

People outside by choice also need to heed the cold.

The St. Louis County Sheriff’s Office reported that it received a call at 10:09 p.m. Monday about an overdue hunter in Beatty Township near Cook, Minn. The man had left home about 1:30 p.m., and his family became concerned when he didn’t return.

He was found about 4:20 p.m. Tuesday. His truck had become stuck and he began walking to find help. The man was taken to Cook Hospital suffering from hypothermia, the Sheriff’s Office said.

Meanwhile, the city of Minneapolis issued a warning Tuesday to keep pets and humans safe during extreme cold spells.

“Everyone should remember: If it’s too cold for them, it’s probably too cold for their pets,” the city said. Anyone who sees an animal outside without shelter should call Minneapolis Animal Care and Control at 612-673-3000.

The city of Minnetonka advised residents about keeping water pipes from freezing. It urged making sure the furnace’s cold-air return is pointed away from water pipes; leaving kitchen and bathroom cabinets open for air circulation, and having someone keep an eye on the house if you’re away.