PHILADELPHIA – If you need a reminder that summer has officially started, just walk outside: Temperatures across the Northeast are expected to approach triple digits.
The National Weather Service has forecast potentially record-breaking temperatures just as the season officially begins Wednesday, the summer solstice and longest day of the year.
Communities throughout the region opened cooling centers for senior citizens and others and planned to keep swimming pools open longer.
Readings are expected to be in the mid- to high-90s Wednesday and Thursday in cities from Washington, D.C., to Boston. Humidity could make it feel even hotter.
Connie Vincent, a mail carrier, was already sweating as she began her rounds in a residential neighborhood in Manchester, Conn., Wednesday morning.
"There's nothing you can do," she said as she dabbed her face with wet washcloths. "Tomorrow's my day off, thank God. I've just got to make it through today."
In Washington, Deborah Otchere, 59, mapped out a tree-lined route to work and brought a change of clothes to her job as a secretary in a law firm. Among her traveling supplies was a partially frozen bottle of water.
"You live here long enough, you know how to prepare," she said.
Health officials warned residents to drink water, stay out of the sun and in air conditioning, and to check on elderly neighbors and pets. For those without air conditioning, cooling centers have been set up in public buildings in dozens of cities.
"You're talking about almost 15 degrees above normal," said Kristin Kline, a weather service meteorologist in Mount Holly, N.J.
Normally, the high for Philadelphia is about 84 degrees — closer to Wednesday's predicted low of 80 degrees. The city's highs in the next couple of days could break decades-old records of 98 degrees, set in 1931, and 99, set in 1923.
The wilting heat is also expected to hit Boston-area residents hard. Temperatures up to 97 degrees were forecast for Wednesday, followed by 99 on Thursday. Current record highs for these dates are 98 and 95 degrees, respectively.
New York is under a hot weather advisory. Temperatures in the city are expected to hit 94 degrees on Wednesday and 98 degrees on Thursday, about 20 degrees hotter than Tuesday.
The city's 1.1 million public school students are still in session for another week, and just 64 percent of classrooms are air-conditioned.
Students were being advised to wear light clothing and drink plenty of water, and schools have been told to limit outdoor playtime, city Education Department spokeswoman Marge Feinberg said.
In Brooklyn, street vendor James Martin said his family's sixth-floor apartment in Coney Island has no air conditioning and can get really hot. But "we open the front door and all the windows, and we get a nice breeze," he said.
On Long Island, Roy Gross, chief of the Suffolk County SPCA, cautioned against keeping pets in vehicles, noting temperatures can reach 120 degrees within minutes.
"Your pet can quickly suffer brain damage or die from heatstroke when trapped in these high temperatures," Gross said.
Forecasts for upstate New York on Wednesday and Thursday called for temperatures to hit the 90s from Niagara Falls to the Vermont border, with highs topping out in the mid-90s in some places.
Philadelphia began a staggered schedule of opening its swimming pools on Monday, a couple of days after schools let out for the year. Nearly two dozen of the city's 70 pools will be open by Wednesday, with another seven opening Thursday.
"We're very lucky that the pools opened yesterday," James Garrow, a spokesman for the Philadelphia health department, said Tuesday.
He added that the city will activate its heat hotline at noon Wednesday and will work with personal care homes, senior centers, libraries and recreation centers to make sure air conditioners are running.
The Southeastern Pennsylvania Transportation Authority, the state's largest transit agency, is keeping a close eye on the heat as well, spokeswoman Jerri Williams said.
The agency planned to have extra maintenance workers to help deal with heat-related switch failures, problems with track expansion and any overhead wire issues on suburban train lines.
In Rhode Island, all regular public buses and trolleys will be free on Wednesday due to anticipated air quality issues.
Moderate relief from the heat should come this weekend.
Contributing to this report were Associated Press writers Jessica Gresko in Washington, Stephen Singer in Hartford, Conn., Patrick Walters in Philadelphia, Dave Collins in West Hartford, Conn., Frank Eltman in Garden City, N.Y., Karen Matthews and Verena Dobnik in New York City, Erika Niedowski in Providence, R.I., Shannon Young in Boston and Mary Esch in Albany, N.Y., contributed to this report.