There will be no rest this Labor Day for the ice men of Crown Heights.

Hailstone Ice, as their 90-year-old Brooklyn icehouse is now called, is busy every summer weekend, when the staff sets up on the sidewalk to face a nearly constant stream of backyard barbecuers, street vendors and snow cone scrapers, dollar water sellers, event planners with warm beers, D.J.s who need dry ice for smoky dance floors, the Dunkin’ Donuts and the Shake Shacks with ice machine issues, and the one lady shipping a week’s worth of food to Burning Man.

But Labor Day is something else — “the last big hurrah,” said Hailstone Ice’s owner, William Lilley. It’s when the neighborhood hosts the West Indian American Day Parade and the pre-dawn J’ouvert festival, plus the million or so revelers that come for them, rain or shine.

“On Labor Day, it’s 24 hours,” Mr. Lilley said. “That’s tradition ever since I can remember, for 30 years, 40 years.”