Not all beachgoers were young people. A retired doctor and self-described “metal detectorist” named Larry Leguire, 68, from Columbus, Ohio, had been in Florida since December. On Thursday on Clearwater Beach, he found four rings, two of which he believed were gold, plus a handful of coins, aluminum cans, pull tabs and bottle caps.

“It was crazy out here yesterday,” Mr. Leguire said. “You saw it, right? Today is a lot less. I think it’s the coronavirus and the news about all the kids congregating.”

Mr. Leguire said he and his wife keep distance from others and wear gloves and masks in grocery stores. He was not happy to learn that the beach was closing Friday night.

“The beach is my life, and without the beach, it’s like, why be in Florida?” he said. “I might as well go back home and sequester myself in my house in Columbus, Ohio.”

Formal gatherings like funerals and weddings were canceled or reconsidered. At a backyard wedding near Anaheim, Calif., on Saturday night, a DJ named Amanda B. was so nervous about performing that she did not shake the groom’s hand or let anyone touch her microphone.

“At that point, the advice was that gatherings of 50 or less were OK,” she said a few days later. “But I wouldn’t do it now.”