Plummeting temperatures in Chicago early Wednesday have made it the coldest Jan. 30 on record, according to the National Weather Service.

The temperature dropped to minus 19 degrees overnight, falling below the previous record low for this day in 1966. The mercury was at minus 22 degrees after 6 a.m., and the weather service said temperatures are expected to move lower as the day progresses. It’s possible Wednesday will break the lowest temperature ever recorded here: 27 below zero on Jan. 20, 1985.

The Chicago Department of Public Health is urging people to stay indoors if they can during the intense cold. People who do need to go out should limit their exposure time, said Dr. Julie Morita, commissioner of the department.

“And make sure that you’re wearing warm clothing. Covering your head, covering your hands, covering your feet, use a scarf, use earmuffs, protect yourself as well as you can so that you are not exposed to extreme temperatures,” she said.

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If Chicagoans are concerned about someone’s safety they can call 311 and the city will do a well-being check.

Most Chicagoans were staying hunkered down at home. But a few ventured out to 31st Street Beach on the lakefront.

Lee Jones was walking her dog despite the subzero cold.

“Because my dog is crazy and she needs to get out,” Jones said. “She loves to go outside. It might be a little cold for even her today.”

Power

ComEd said there were about 20,000 customers without power as of 8 a.m. A spokesman for the company said it was safe to assume the outages were due to the cold, but a specific cause was not clear. ComEd said most of the outages were in the south suburbs, and in Streator and Pontiac.

Trains

The South Shore Line, which runs into northern Indiana, suspended its commuter rail trips for Wednesday and said it expected to offer limited service on Thursday. South Shore said normal service would not resume until Friday.

Extreme weather conditions earlier prompted Amtrak to cancel all trains into and out of Chicago on Wednesday and most services to or from Chicago on Thursday.

The Chicago Transit Authority had planned to run buses and trains on normal schedules, but the agency was modifying some train schedules Wednesday morning because of maintenance and other cold-related issues. Trains were running at 10- to 20-minute intervals on some lines, rather than at shorter intervals.

Metra will be operating on a modified schedule Wednesday and Thursday due to the subzero conditions, which can create switching problems on train tracks. Visit Metra’s website for schedule updates.

Airports

More than 1,600 flights have been canceled at Midway and O’Hare airports, according to the city’s aviation department. Air travelers are being urged to check their flight status with their airline before heading to the airport.

USPS is also suspending service in parts of central Illinois and Chicago zip codes 606- to 608.

Due to the extreme weather conditions caused by Winter Storm Jaden, we have temporarily suspended delivery service in certain locations to ensure the safety and well-being of our employees. Visit our Service Alerts page for more details. https://t.co/tUQeYYLl8g pic.twitter.com/M95kaHU4Y1

— U.S. Postal Service (@USPS) January 30, 2019

Schools

Chicago Public Schools canceled classes Wednesday and Thursday. The closures come during finals week for many high schools, forcing exams and grades to be delayed in some schools. CPS students will also be off on Friday for a previously scheduled staff development day.

Hundreds of public and private schools across the Chicago area are closed. The Emergency Closing Center maintains a list.

Many colleges are closed through the end of the day Thursday, including DePaul and Northeastern Illinois. Other schools, such as the University of Illinois at Chicago and Northwestern, plan to reopen at noon on Thursday.

Help for the homeless

Chicago officials say the city is implementing extreme weather plans, including deploying warming buses to assist homeless residents, adding shelter beds, and creating two 24-hour warming centers. City facilities, including community centers, park houses, libraries and police stations will also serve as warming centers. Residents seeking access to warming centers are encouraged to contact 3-1-1 for immediate assistance.

Want to survive today’s #PolarVortex2019? “Put baked potatoes in your pockets,” says former Chicago Tribune health reporter @JulieDeardorff https://t.co/ANb9N9b90T

— Curious City (@WBEZCuriousCity) January 30, 2019

Courts not in session

The Chicago #Immigration court is closed today and tomorrow Jan. 31 due to the weather.

— Maria Ines Zamudio (@mizamudio) January 30, 2019

Among the things the arctic cold is freezing temporarily are the wheels of justice. Many federal and state courthouses are closed Wednesday, with some closing Wednesday and Thursday. The chief judge for the circuit courts in suburban Chicago, Susan Clancy Boles, cited the “dangerous cold” for the decision to close both Wednesday and Thursday.

Check back for updates.