The heat in the city is such that even a policeman guarding Criminal Court on Centre Street called it cruel and unusual.

As the temperatures approached the record books — yesterday’s peak at Central Park was 95 degrees, and the 98-degree high at La Guardia Airport broke a seven-year-old record — an A train in the Rockaways lost power after heat buckled a section of the third rail. Con Edison reported a manhole fire in Astoria, and a spokesman said about 180 customers citywide were without power; it was investigating whether heat caused the outages.

Agencies citywide extended the hours of public pools, offered free spray caps to place on fire hydrants, and opened hundreds of cooling centers.

To walk through Lower Manhattan yesterday afforded a view of widespread efforts to steal a respite from the day’s oppressive heat: children frolicked by sprinklers, some men chose to go shirtless, and a City Hall press conference relocated to the portico from the storied steps.

The cooling centers were especially valuable for older New Yorkers such as Robert Wong, an 89-year-old Lower East Side resident whose home lacks air conditioning.

Mr. Wong said he found himself at a cooling center on Gold Street the morning after he’d spent Sunday evening “hanging around on the street” until 11 p.m. because his home was just too hot. Off the street, Mr. Wong spent a lazy afternoon sipping water in an air-conditioned room with almost a dozen oscillating fans watching fellow senior citizens do yeun-chi exercises.

The City Hall cooling center got about 15% more visitors than usual for yesterday’s free lunch, the center’s director, Fay Matsuda, said. But not all of the city’s 350 or so cooling centers saw a spike. At the Rutgers Community Center on Madison Street, a main entrance was locked. The center’s director, Zach Husser, propped the door open with a plastic fork as he explained that not a single person — except a woman taking a bathroom pit-stop — had taken advantage of the air-conditioned center.

The city’s Office of Emergency Management didn’t report a spike in heatrelated medical activity, according to a spokesman, but Dr. Kristin Harkin of New York-Presbyterian Hospital estimated she had seen a 40% across-the-board upsurge in visits, ranging from heat exhaustion to the exacerbation of illnesses like asthma and diabetes.

Her best advice to New Yorkers? Drink water. Lots.