BOSTON — The bitter cold kept its grip on the Northeast on Saturday, while warmer temperatures brought relief to the Midwest and Southeast.

A day after schools in a dozen states closed and Alabama was colder than Alaska, temperatures in the South climbed into the 40s, thawing water fountains and pipes. The Northeast, however, persisted under chilly air from Canada for another day with temperatures barley climbing into the teens in some places.

In Boston, the Pine Street Inn shelter sent out vans to look for the homeless during the day, rather than just at night, said shelter spokeswoman Barbara Trevisan. The shelter also expanded its hours and is serving an extra meal.

“From what I’m hearing, it’s the coldest it’s been in a number of years,” she said.

Trevisan said the shelter, which holds about 700 people, has been packed in recent nights as temperatures dipped below zero.

The weather led to at least seven deaths and contributed to dead car batteries and dozens of accidents. In northeast Ohio, authorities said an 8-year-old boy drowned Friday after he fell into a partially frozen creek and got stuck under the ice. Temperatures had reached several degrees below zero in the town of Mentor, Ohio.

In Illinois, the deep cold that seized the state for two days eased, leaving flooded rivers and frozen waterways in its wake.

Temperatures reached the low 30s in central Illinois and the low 20s in the northern part of the state Saturday — balmy compared to the subzero weather that forced people to hide their grimaces behind scarves and ski masks. The National Weather Service said it had been the coldest episode in northern Illinois since February 1996.

A Catholic school in Chicago was investigating how a 6-year-old boy was left sleeping on a school bus for more than two hours in subzero temperatures. Farther southwest in suburban Chicago, ice blocked water along the Fox River, causing minor flooding. One family was forced to evacuate a home.

At least five tow barges became locked in ice on the lakes near Peoria, said Mike Cox, operations manager with the U.S. Army Corps of Engineers’ Peoria office. Ice also caused barge traffic to slow along the Illinois River.

In upstate New York, where temperatures in some communities had dipped below minus 30 during the cold snap, Saturday’s highs were forecast to be in the mid teens near the Canadian border.

In Michigan, a winter storm watch was in effect for parts of the Lower Peninsula, where up to 8 inches of snow could fall by Sunday morning, the National Weather Service said.