PHILADELPHIA - The eastern U.S. cooked for another day Wednesday as unrelenting heat again sent thermometers past 100 degrees in urban "heat islands," buckled roads, slowed trains and pushed utilities toward the limit of the electrical grid's capacity.

Philadelphia hit 100 degrees for second straight day, breaking a record of 98 degrees set in 1999. Baltimore hit 100 for the third straight day and Newark, N.J., hit triple digits for the fourth straight day. New York's Central Park was at 99 degrees at 2 p.m.

Sue Robels, 22, was getting out of the heat at Philadelphia's Franklin Institute science museum for an exhibit on Cleopatra.

"My apartment isn't air conditioned, so it's going to be museums, movies, Starbucks, anywhere else but at home today," she said.

Scattered power outages affected customers up and down the coast and usage approached record levels. In the Washington, D.C., area, nearly 1,000 customers were without power Wednesday, while New Jersey's largest utility, Public Service Electric & Gas, reported about 6,300 customers without power. Consolidated Edison in New York said it was working to restore power to about 6,300 customers, down from outages to 18,700 customers Tuesday.

Tatiana Solis, 17, was getting ready to deliver newspapers Wednesday in New York City, where forecasters predicted a high of up to 99 degrees.

"I have asthma and when it's hot, it's too exhausting," she said. "I can't breathe."

In Reading, Pa., Lisy Colon brought three of her grandchildren to a Salvation Army cooling station. Colon has diabetes and said she worried she would succumb to the heat inside her daughter's apartment, leaving the children - an 11-year-old and 2-year-old twins - by themselves.

"I was so scared. I said, 'We're not staying here today,'" Colon said as her grandchildren played basketball inside. "For me, it was too hot."

The heat also forced nursing homes with power problems to evacuate and buckled highways near Albany and in the Philadelphia area. On New York's Long Island, a radio station was distributing free bottled water to day laborers, while human services workers in Pittsburgh were doing the same for the homeless there.

The hot weather is especially dangerous for the elderly, but even the young and fit were having trouble.

The U.S. Naval Academy said four midshipmen who had just completed an obstacle course needed medical attention for possible heat exhaustion after they completed an endurance course that included climbing cargo netting and jumping over logs. In Middletown, Conn., police charged two high school assistant football coaches with reckless endangerment after a player collapsed while running an uphill sprint Tuesday evening.

New York, Philadelphia, Baltimore and other dense, built-up areas are getting hit with the heat in a way their counterparts in suburbs and rural areas aren't. Cities absorb more solar energy during the day and are slower to release it at night.

But it was also hot at the beach.

Sharon Delano, of Lancaster County, Va., spent Wednesday morning in the Carolina Beach, N.C., arcade to escape the heat. Sitting at a picnic table near a massive fan, she watched her kids play video games with her mother, Carol Davis.

Davis appreciated the sea breeze and said frequent dips in the ocean helped keep her cool, but the family needed a break from the heat.

"With that breeze blowing, you don't know how bad you're getting burned," said Davis, 63.

Transportation officials cut the speed of commuter trains in suburban Washington, D.C., and New York when the tracks got too hot. Extreme heat can cause welded rails to bend under pressure. Some New Jersey trains were canceled and rail-riders were advised to expect delays.

In Park Ridge, N.J., police evacuated a nursing home and rehabilitation center after an electrical line burned out Tuesday evening. In Maryland, health officials moved all 150 residents out of a Baltimore nursing home whose operators didn't report a broken air conditioner. The state learned of the home's troubles when a resident called 911 Tuesday.

Residents of two Rhode Island beach towns, Narragansett and South Kingstown, were hit with an added layer of inconvenience: They were banned from using water outdoors and were asked to boil and cool their water before using it. The high temperatures combined with the busy holiday weekend for tourists created higher-than-expected demand, causing water pressure to drop and increasing the chance of contamination.

In Boston, the sweltering temperatures pushed a window-washing company to adjust its hours.

Victor Cruz, 24, usually starts his day with Cliffhangers Inc. at 6:45 a.m. But on Wednesday, he was washing ground floor doors and windows at Boston's Intercontinental Hotel starting at 4 a.m., so his day would end at noon, instead of 3:30 p.m.

"It's just exhausting," Cruz said, pining for the days he used to work in a bank. "I actually took Tuesday off because it was just too hot. When it's like this we'll sit in the van every so often with the air conditioner on for a few minutes just to cool down."

Karin Korpowski-Gallo, a spokeswoman for the National Zoo in Washington, said most of its animals have access to air conditioning.

"The pandas aren't big fans of this kind of heat," she said of the zoo's most famous animals. "They choose to stay indoors and they sleep a lot."

Deaths blamed on the heat included a 92-year-old Philadelphia woman whose body was found Monday and a homeless woman found lying next to a car Sunday in suburban Detroit.

With people cranking up their air conditioners Wednesday, Valley Forge, Pa.-based PJM Interconnection - which operates the largest electrical grid in the U.S. - urged users to conserve electricity as much as possible, especially in the peak afternoon hours. PJM's grid covers about 51 million people in 13 states and the District of Columbia.

Meteorologists in some places began calling the current hot stretch a heat wave, defined in the Northeast as three consecutive days of temperatures of 90 or above.