We find ourselves this week simmering in the geothermic core of July.

It is hot.

So hot that the sidewalk outside the Payless shoe store on Chestnut Street makes melted cheese of your flip-flops.

So hot that to sit at the outdoor tables at Serafina's on South 18th constitutes cruel and unusual punishment.

So hot that to keep his scalp from scorching as he hauled old windows into a trash bin on Chancellor Street, Paul Bey packed his hard hat with paper towels, hosed down a blue microfiber towel, slapped the whole thing onto his head, and created one cool, fetching chapeau.

"Sweating is OK," said Bey, 54, who has worked for Laborers Local 332 for 26 years in every extreme iteration of nature.

Given the choice, he'd rather wilt than shiver. Uncomfortable but unfazed, Bey reached for a bottle of water stuffed into his front jeans pocket.

On Tuesday, the fourth heat wave of the season became official - a third consecutive day of 90-plus heat.

Not as bad as the high mark of 102 set in 1988, but plenty uncomfortable. Philadelphia did set a record, though, Tuesday. The temperature bottomed out at 81 early in the morning, making it the highest low temperature for a July 16 since meteorologists began keeping score in 1874. The previous record was 77.

Overnight-warmth records will be challenged the rest of the work week. Afternoon highs are expected to reach the mid- to upper-90s through Saturday as a high pressure system off the Atlantic Coast steeps the region in warm, damp air from the subtropics.

"Every day gets a little worse," said Tony Gigi, meteorologist at the National Weather Service office in Mount Holly. "Saturday looks miserable."

For a guy like Dave Lopez, who makes a living grilling hot dogs in a food cart, misery is relative.

In Conshohocken on Tuesday, Lopez, who operates the Race to Taste Curbside Grill on Fayette Street, took a so-what approach to the heat.

"Weather is weather," he said, smearing ketchup and mustard on a hot dog for a customer. "We're all going to live if we drink water."

A few blocks away, on Spring Mill Road, a contractor, Bud Slemmer, was preparing to repair a gas line. Already wearing jeans and boots, he threw on a heavy leather coat, work gloves, and a welding mask.

On Monday, Slemmer said, he and his crew used an infrared thermometer to take the temperature of their microenvironment.

The results were both impressive and alarming: The inside of a hard hat, 103 degrees. Boots, 110 degrees. Pavement, 122.

Coping with heat could not be simpler, said Slemmer's fellow crew member Mike Hardcastle.

"Water, water, water," Hardcastle said, laughing.

At the Elmwood Park Zoo in Norristown, however, water does not cut it.

To tend to the particular tastes of her charges, animal keeper Rachel Killeen must freeze blood, fish, and fruit into large cubes of ice.

"We have to get crafty," Killeen said. "If the frozen water tastes like blood, then it's delicious for them."

(Bella and Edward, eat your hearts out.)

At the Philadelphia Zoo, a pair of 32-year-old polar bears, Klondike and Coldilocks, had access to temperature-controlled dens.

They preferred, however, to cool down in their 125,000-gallon pool. Klondike, a lithe 475-pounder, lounged in the water, lifting her face to the cold mist from a custom-made water sprinkler.

Tammy Schmidt, curator of carnivores and ungulates - that is, animals with hooves - came prepared, with ice treats filled with blueberries and peanut butter. Coldilocks watched from poolside as Schmidt launched the blocks of ice, as big as lunch boxes, into the water. Seconds later, the bear threw herself in, with enthusiasm if not grace, and floating face-first, swatted at the snacks.

"I'm jealous," said Holly Rodriguez, who brought her three daughters from Lebanon, Pa. "I want to jump in the water."

Which was precisely George Jerome Shields' solution.

Shields, a first grader from Kensington, spent much of the afternoon swimming in the fountain at LOVE Park under his grandmother's protective watch. Climbing out of the water, goose-bumpy and grinning, he agreed to answer the burning question, "What is your favorite part of summer?"

"Getting wet!"

Far, far away in Sea Isle City, N.J., it was a war in the hot sand.

Some armed themselves against the no-breeze heat with the latest in solar defense technology - fancy tents, canopies, and UV-resistant rash guards. Others literally blistered asleep in a chair, naked sunburned children half-napping beside them.

But there were no rookie mistakes at the 40th Street beach. Here, they went old school: five mothers, eight children, 13 beach chairs, and seven umbrellas, three patched with duct tape. Two more available if needed.

"Once you step out from under the umbrellas, it's bad," said Lisa Carr, who said the various families - the Carr, Bentz, Helms, Wilson, Robinson mothers and children, fathers there on the weekends - have been gathering at that beach for a decade. They hail from Plymouth Meeting, Haddon Heights, and Philadelphia.

Behind the outdoor bar at the Carousel, manager Mark Eidenberg put his job in perspective.

"We're saving lives up here at the Carousel," said manager Mark Eidenberg behind the outdoor bar, "one beer at time."