Forecast calls for frigid temps

It’’s unseasonably cold and getting colder.

That’s the message the National Weather Service is sending to Bostonians.

Temperatures are usually in the low- to mid-30s this time of year, but starting Wednesday temperatures will be in the low- to mid-20s. With the windchill, temperatures could dip to 20 to 25 below zero.

That, in case you were wondering, is really cold, even by New England’s frigid standards.

According to the Boston mayor’s office, a low of 0 degrees would be the coldest reading in the city in four years. The city has only reached 0 or subzero twice in the past decade – in 2011 and 2005.

“We are very concerned about this cold weather and are working to monitor the situation and keep all our residents safe,” said Mayor Marty Walsh. “While we’re doing what we can to spread this information city-wide, I’m personally asking each and every single Boston resident to look after their neighbor, be it someone you see outdoors or someone living next door.”

Meteorologists from the service’s Taunton office expect winds of 10 to 15 miles per hour Wednesday night, with gusts up to 30 degrees.

The state could see some snow squalls late Wednesday afternoon, but any accumulation will likely happen west of Route 495.

On Thursday, temperatures will struggle to reach 20, according to the service.

“There’s an arctic cold front that’s going to bring in those really bitter temperatures,” said Alan Dunham, a local meteorologist for the National Weather Service. “If anyone’s going out Wednesday or Thursday, make sure you’re doing it in layers.”