The orange brick Spring Garden School in North Philadelphia resembled a clay oven Wednesday afternoon.
Inside the steamy behemoth described as "hell" by teacher assistant Karen Green, temperatures reached 90 degrees or more in places, principal Laureal Robinson said.
Staff and students figured they were in trouble when the kindergarten-through-eighth-grade school was declared unbearable by someone who should know: math teacher Judith Grant, a native of Jamaica.
"Oh, it's hot," she said, dabbing her forehead. "It's a challenge to be in here."
The sweltering school's 320 students were dismissed nearly two hours early, at 1:30 p.m.
Similarly, schools in New Jersey and Pennsylvania suburbs shut down early as temperatures climbed through the 90s.
By 3:29 p.m. Wednesday, Philadelphia had reached its official high temperature of the day, 97 degrees, breaking the record of 95, set in 2005. As the region braces for another day of heat, meteorologists will keep an eye on Thursday's record high of 98 degrees, set in 1933. Philadelphia public and archdiocesan schools will close at 1:30 again Thursday.
"My teachers are cranky and grouchy," Robinson said. "The students become less tolerant. It's difficult to maintain an environment that's conducive to learning."
Students with classes on the stifling third floor learned an important lesson in physics: Heat rises.
"We were bunched up in class on the third floor, and the heat made some kids grumpy and some kids quiet," said Tatyana Davis, 12, a sixth grader. "It made my head hurt."
Fans were plugged in and switched on high, but all they did was bat the broiling air, enveloping the children in a desert wind.
A few school offices are air-conditioned, but that particular news was of no use to eighth grader Daquan Hamilton, 14, eating lunch in the stifling basement cafeteria.
"It's kind of stressing to be in here," he said. "It's hard to wake up."
Knowing that Thursday may get to 100 degrees, Eulane Fowler, on hand to pick up 6-year-old granddaughter Kyiana Thomas, a first grader, wondered whether school should be closed.
"It's too dangerous," she said. "In the city, hospitals will be full tomorrow."
Fearful of a torrid Thursday, Ridley School District Superintendent Lee Ann Wentzel announced that the district's seven elementary schools, which are not air-conditioned, would be closed.
The middle school, which is two-thirds air-conditioned, and the fully air-conditioned high school were expected to open.
In the West Chester Area School District, eight of the 10 elementary schools dismissed pupils early Wednesday and will do so again Thursday, spokesman Rob Partridge said.
"When it becomes 95, 96 degrees, it's untenable," he said, adding that "the safety factors all add up."
It was business as usual at the high schools in Delaware County with air-conditioning.
Of those without, Cardinal O'Hara was closed for graduation, while students at Monsignor Bonner and Archbishop Prendergast Catholic High School were busy with exams and had already planned an early dismissal.
Meanwhile, students on a shortened day Wednesday streamed out of Haddon Township schools into the scorching heat. Some already had plans.
Sherri Keating's 13-year-old son, Andrew, a seventh grader at William G. Rohrer Middle School, was looking forward to playing video games at home.
Even under a relentless sun, it appeared that teacher aide Michelle Dayton's 8-year-old grandson, Luke, could not be stopped. He hurried to romp with friends in the school playground.
"It doesn't matter if it's 10 degrees or 100 degrees," Dayton said. "He wants to play."