It’s freezing on the streets of Boston, and authorities are urging anyone out there to seek shelter — or at least to warm up inside for a few hours.

“All of our shelters are open 24/7, obviously during the day and the night so anyone can come in,” Pine Street Inn president and executive director Lyndia Downie told the Herald in an interview Tuesday. “Even if you don’t want to come in and spend the night, come in and take a bed or a couch and come in to get warm.”

It barely reached 20 degrees in real temps on Tuesday, and the local National Weather Service station projects that wind chills will plunge into the single digits over the next few days.

Downie, who has run Boston’s Pine Street Inn network of shelters for around 40 years, said that following the milder last couple winters, the frigid temperatures may have taken some people who live on the streets by surprise.

“They sometimes get caught off-guard when it gets this cold,” she told the Herald in an interview Tuesday. “They aren’t necessarily thinking it through.”

Pine Street Inn offers four shelters in the city, with the majority of their 650-some sleeping spots located in their South End headquarters.

Coming out of COVID, she said, Pine Street had around 450 beds and the organization has added another 90 of them through the last year. In addition to the beds, she said the Inn also offers sleeping “spots,” that is mats and cots that help to increase capacity.

But she said she realizes that not everyone wants to stay the whole night in a shelter. Those people, she urges, should at least come to a shelter “warming center” for a few hours to get out of the cold.

“Come in for a few hours, warm up,” she said. She added that workers would allow people to sit in the van that goes around the city, too, as a way to warm up. She said that the shelters also offer soup and sandwiches for those in need.

But the Pine Street Inn is not an emergency response organization, she cautioned. Boston residents who are concerned about people they see should call 911, as the police and ambulances will be faster and better able to assist in emergency situations.

Boston Police spokesman Detective Sgt. John Boyle told the Herald that dispatchers read a set instruction twice a shift, or six total times throughout each day, during extreme cold that reminds officers of the need to assist people out in the elements.

“It shall be the policy of the Boston Police Department that no person, regardless of his or her means, will be forced to spend the night time hours on the street during the winter months,” a police memo on the order states. “Officers will closely monitor their area of patrol to identify and transport to a shelter facility any person who is without shelter.”

The Pine Street Inn urges anyone who is aware of someone who may be in need of outreach services to call them during the day at 617-892-9572 or at night — 9 p.m. to 5 a.m. — at 617-633-0170. Those who need assistance themselves can call triage staff at 617-892-9228 from 10 a.m. to 6:30 p.m. every day.