Walk into one of the only Manhattan ice skating rinks open for the summer, and the milieu — the window shades pulled down tight to keep the room ice-friendly at 54 degrees — could melt the memory of the Big Apple’s outdoor sauna from your mind.

During the recent heat wave, Chelsea Piers “started getting flooded with calls … for people wanting to skate and basically cool off,” the director of figure skating, Kenny Moir, said yesterday as satellite radio ditties softly serenaded skaters.

At Pier 61 in Chelsea, lunchtime figure skaters mix with young summer campers at the 24-hour polar encampment by the Hudson. With the skating rinks at Wollman Rink, Rockefeller Center, and Bryant Park closed for the summer, Chelsea Piers’s Sky Rink provides a rare summer service.

On a typical day, haggard has-beens show off camel spins as children — distinguished from one another perhaps only by their colorful T-shirts — squeak, circling and circling and circling the rink. A few young vets whiz by, others mosey along, then try to whiz by and slip, fall, and cry, triggering staff sentries on skates to rush over, pick them up, and send them on their way.

Whether skaters are veterans or naïf passers-by seeking icy relief, patrons get a gratis cool down.

“Most people are able to get moving and at least enjoy the whole process,” Mr. Moir said.

The 35,000-square-foot ice rink — which sports an emergency generator that came in handy during the 2003 blackout — is proving an increasingly irresistible interlude as Gotham’s temperature rises: between June and July, the number of skaters at Chelsea Piers has increased 72%, according to a spokeswoman, Joanna Shapiro.

The increase came as the available time for anyone with $11 to come in to skate decreased by more than nine hours. Pier 61, home to an east and a west rink, also hosts competitive hockey leagues, ice and figure skating lessons, and, this week, more than 750 campers from the tristate area.

One of Sky Rink’s patrons that skates not because she’s a camper, but, well, just because is LeAnn Yee of Battery Park City. The figure-skater spent lunchtime yesterday doing turns and waltz jumps and other icecapades one usually sees only during Olympic telecasts.

“It’s a great place to go during the summer,” Ms. Yee, who used to skate years ago at the crack of dawn before she went to work in finance, said. “It’s like someone else is paying for air-conditioning.”