After the weekend snowfall, temperatures are plummeting Monday, with highs barely reaching the low 20s in the Baltimore region, according to the National Weather Service.

Brisk winds with gusts of 25-30 mph will make conditions even colder, bringing wind chills down to single digits and below zero. Authorities are warning drivers to use “extreme caution” on the roads, and multiple school districts delayed the start of classes Tuesday.

Baltimore residents saw less than two inches of snow on Sunday, according to the weather service.

In the Baltimore region this week, don’t expect the snow or leftover ice to melt, said Kevin Whitt, a meteorologist with the weather service.

The temperature is only expected to reach a high of 25 degrees Monday before dropping to about 10 degrees at night. The wind gusts will make it feel even colder, about 8 degrees in Baltimore and sub-zero north of the city.

Tuesday’s warmest temperature is anticipated to be 22 degrees, with a low of 7 degrees at night, according to the weather service.

The winds will diminish through the week, but it will still feel cold and there is another slight chance of snow Tuesday night, Whitt said, adding that vulnerable pipes could freeze. Let them drip a bit, he advised.

Baltimore is under a code blue alert until Thursday, Mayor Brandon Scott posted on X. He asked for residents to check on vulnerable neighbors and to call 443-984-9540 to find nearby resources or shelter.

Baltimore, Baltimore County and others said schools would open would open delay the start of classes by two hours on Tuesday.

Like earlier this month, this latest cold snap comes from a disruption in the polar vortex, the ring of cold air usually trapped about the North Pole.

The cold air will moderate as it moves southward and eastward, but the central and eastern U.S. will still experience temperatures in the teens and 20s Monday into Tuesday, said Marc Chenard, a meteorologist with the National Weather Service in College Park. The mid-Atlantic and Northeast will also have highs in the teens and 20s, lows in the single digits and below zero degrees F (minus 18 C), and wind chills below zero.

Chenard projected that as many as 70 million residents will be under some kind of winter storm warning in the coming days.

Baltimore’s winter advisory lifted at 7 p.m. Sunday.

Monday’s weather makes for a colder than average Inauguration Day. The coldest was in 1985, when 7-degree temperatures forced the swearing-in ceremony for Ronald Reagan’s second term to move inside the Capitol Rotunda, just like President Donald Trump’s.

State Highway Administration snow removal crews are out and about to patrol for icy patches on the roads from the extreme cold. The highway administration is closed today in observance of Martin Luther King Jr. Day.

For those out on the roads, “use extreme caution … [and] make smart travel decisions,” the highway administration said in a Facebook post. Travelers should monitor chart.maryland.gov to track real-time incidents and gain access to hundreds of live traffic cameras.

For narrow and steep streets around the city, Baltimore’s Department of Transportation is encouraging residents to use the beloved yellow salt boxes. Don’t have one on your street? Residents can send a request for a box through 311.

Residents can also call 311 to report road conditions and issues with trash pickup and recycling.

Baltimore Banner reporter Meredith Cohn and the Associated Press contributed to this report.