In the stifling subway tunnels, there was no air conditioning on three cars of the train Sayed Bukhari rode into Manhattan.
"People were crying," Bukhari said.
The National Weather Service posted heat advisories and warnings from Maine to Oklahoma. Triple-digit temperatures were forecast Wednesday along the East Coast as far north as parts of Maine and New Hampshire.
And don't look to the nighttime for any relief.
Research shows the United States in recent years has been sweltering through three times more than its normal share of, government weather records show. And that is a particularly dangerous trend. From 2001 to 2005, on average nearly 30 percent of the nation had "much above normal" average summertime minimum temperatures, according to the National Climatic Data.
The temperature was already above 80 before dawn Wednesday at Nashua, N.H. New York's LaGuardia Airport still had 92 degrees at midnight and eased only to 86 degrees by 6 a.m., the National Weather Service said. In the heart of crowded Manhattan, the low at Central Park only got down to 83.
New York City Mayor Michael Bloomberg declared a heat emergency, CBS News' The Early Show weatherman Dave Price reports.
"It feels like we're having a barbecue in Zimbabwe right now," a commuter told Price.
Equipment problems and stormy weather caused scattered power outages during the night in parts of New England, shutting off fans and air conditioners, utilities said.
Electricity usage in the six-state New England region could top 28,000 megawatts Wednesday, breaking the one-day record of 27,395 megawatts set just two weeks ago, according to Erin O'Brien, a spokeswoman for ISO New England, which oversees the region. The demand Tuesday was just shy of the record, she said.
The hot weather brought its share of troubles Tuesday, putting animals in jeopardy, disabling cars and prompting New York to turn off lights atop the Empire State Building.
CBS News correspondent Bob Orr reports that 1,200 residents on Chicago's South Side were evacuated from high-rise buildings by the hundreds on Tuesday, one day after the power went out to 20,000 customers. Illinois officials blamed three deaths on the heat.
A 15-year-old high school football player died in Georgia, one day after collapsing in the heat at practice, and the heat was suspected in the death of a 75-year-old woman in Wisconsin who kept the air conditioning off to save money.
To the north and west, some areas had started to enjoy a break from the heat. Hayward, Wis., cooled to 70 on Tuesday, down from 104 degrees on Monday.