The temperature in the parking lot was dropping toward 30, but the thermostat inside the Maple Shade Custard Stand registered an almost balmy 68 degrees.

Painted red and white with the iconic "Drive In" sign on top, the stand saw a slow but steady flow of customers on a frigid evening two days before Christmas Eve.

Inside, college students Lauren Shipton and Corrin Sloan were working the counter and feeling merry, forgoing their standard-issue "Got Jimmies?" T-shirts for hoodies and sweats, better to stay warm when they slid the plexiglass window open for a customer.

"Everyone says, 'We must be your only customer.' They always say that," said Sloan, 19. "It's not like the summer, but there's always customers, even when it's snowing. And they come from all over."

In summertime, custard stands are a popular part of South Jersey life, a place to drive with the children or a date, to sit on a bench and soak up a late summer evening with a Styrofoam cup filled with soft-serve ice cream. By late autumn, most have shut down.

But not in Maple Shade.

The story of how the custard stand at the intersection of Coles Avenue and Main Street came to stay open through the dead of winter is not particularly compelling, owner Joe Fischer explained.

It was the mid-1990s, and he had been running the business for about five years when he realized he had steadily pushed up his opening date, and moved back his closing date, to the point that spending the money to close down and winterize didn't make a whole lot of sense.

So that winter he stayed open. He quickly realized he had tapped into a wide-open market for midwinter ice cream fanatics.

"There's a sledding hill across the street, and the kids usually come by when they're done. So I thought I'd try selling hot chocolate and soups, but it didn't work," he said. "We sell a lot of milk shakes in winter. It doesn't make any sense, but that's it."

As the wind gusted around the custard stand Thursday afternoon, a line formed in the parking lot. Women in skirts braved the cold for a custard, shivering in their Ugg boots.

Chris Ward, an insurance broker from Cherry Hill, was heading out the next morning for a family vacation to Disney World, but had stopped off for one last ice cream.

The question of whether custard was any less appropriate a treat in winter struck him as missing the mark.

"It's the same," he said. "Plus it's not going to melt. You don't have to worry about eating it so quickly."

Soon the line had cleared, and the parking lot was quiet.

For the young women who work the counter, the slower pace was a drastic change from summer, when there's a perpetual line and seven or eight workers are crammed into the shack, smiling brightly even in the face of the occasional difficult customer.

The jobs are highly coveted by Maple Shade teenagers and, once acquired, are usually held onto until college graduation.

"Every girl has a story about how she got her job here," explained Sloan, whose mother and aunt worked at the stand. "I used to be best friends with the owner's daughter in elementary school. Of course, we're all best friends here. I love it."

The nostalgia for the stand, which Fischer said opened in the late 1950s, extends to the customers as well. Some of them remember visiting the stand with their parents just as their children now do with them.

On Wednesday night, as the traffic to the nearby Cherry Hill Mall started to build, Donald Stearns, a 62-year-old biology professor, pulled into the lot.

The moon, nearly full, hung in the sky. Christmas lights on the surrounding homes twinkled.

But as Stearns shivered in the lot with his "vanilla with cherry icy in-between," he said it was too cold to stand outside and eat.

"I already had my dinner, baked chicken with peas," he said. "I'm going to go home, watch some TV, and enjoy this."

Contact staff writer James Osborne at 856-779-3876 or jaosborne@phillynews.com.