Residents of the Eastern and Central United States braced for another day of scorching heat Saturday as record-breaking temperatures forced Americans to seek refuge in swimming pools and air-conditioned malls.

Forecasters predicted little respite at least for another day as a giant heatwave swept across half of the country.

Newark, New Jersey saw an air temperature of 108 degrees Fahrenheit (42 Celsius) Friday, the highest ever recorded in the city since records began there in 1931, and the hottest reported by the National Weather Service on the East Coast.

At Dulles Airport near Washington, temperatures hit 105 degrees Fahrenheit (41 Celsius), the highest since the facility opened in 1962.

Two cities in Connecticut, Hartford and Bridgeport, also set all-time temperature records as the mercury touched the 103 Fahrenheit (39 Celsius) mark.

A dozen other towns, cities and airports up and down the East Coast set triple-digit Fahrenheit records for the calendar day, as did New York's Central Park, where the read-out on thermometers showed a temperature of 104 Fahrenheit (40 Celsius).

Inside the old townhouse in northeast Washington that Ben Dooley shares with two housemates, the temperature was pushing 91 degrees Fahrenheit (33 Celsius).

That was the temperature indoors.

Outdoors in Washington, the mercury climbed to 101 Fahrenheit (38 Celsius) Friday, but high humidity made temperatures in the US capital feel more like 116 Fahrenheit (47 Celsius) -- hotter than Death Valley at daybreak.

From Texas in the southwest to Maine in the far corner of the northeast, more than half of the 50 US states were under extreme heat warnings with the record temperatures and high humidity reportedly claiming at least 22 lives in the past week.

"Bullseyes of high heat and humidity" were affecting the central states and most of the East Coast, said Chris Vaccaro, a spokesman for the National Weather Service.

Triple-digit temperatures were recorded in Islip, Long Island, which is usually cooled by Atlantic breezes; Philadelphia, Allentown and Reading in Pennsylvania; Georgetown in Delaware; Boston, Massachusetts; the East Coast gambling Mecca of Atlantic City in New Jersey, and Baltimore in Maryland.

Even Bangor, Maine, which lies at the same latitude as Montreal in Canada, reached a record for the calendar day of 97 Fahrenheit (36 Celsius).

To beat the heat, people streamed to swimming pools, spent long hours in air-conditioned museums or shopping malls, or sat inside the foyers of public buildings that were opened as cooling centers.

Philadelphia, the "city of brotherly love", became the city of smothering heat, with temperatures at 102 Fahrenheit (39 Celsius) by late afternoon.

Public swimming pools in the Pennsylvania city were so crowded that swimmers were asked to leave every 30 minutes to allow a new crowd to enjoy a cooling dip.

Maryland's Hidden Spring camp for kids aged up to 14, called off a much-anticipated hike to a waterfall and took the 45 campers bowling instead.

"It didn't seem wise to take the kids hiking. They're disappointed and so are we, but an air-conditioned bowling alley seemed a good trade-off for triple-digit heat," camp director Eric Fishman told AFP.

In New York City, the Office of Emergency Management opened cooling centers in air-conditioned public facilities for people "experiencing physical discomfort in the heat wave."

And the Washington public transportation system lifted its ban on drinks in trains and buses -- although it stressed that the exception to the rule applied to bottled water only and would end after Sunday night.

Nightfall has brought little respite from the heat, with temperatures only falling to lows in the 70s or 80s Fahrenheit (20s Celsius).

"That's one of the unhealthy aspects of this heatwave: temperatures aren't retreating at night, and that taxes the body. Last night in DC, the low was 82," Vaccaro said.

Dooley described the previous night in his room without air conditioning in northeast Washington as "unbearable" and admitted that, although not a fan of air conditioning, he was considering "camping" in his housemate's room, equipped with a window air conditioner."

As many as 34 states at a time have been under heat advisories since the latest surge in the heatwave began a week ago in the Midwest before moving eastward.

The high temperatures and humidity are expected to continue into the weekend until a cold front -- or less-hot front -- is forecast to move in.