The water temperature near Key Biscayne, a barrier island just east of Miami, already passed 89 degrees one morning this week. And although South Florida’s ocean was slightly cooler than the recent record highs that stunned scientists and threatened marine life, it remained phenomenally warm.
But on this serene patch of Atlantic Coast, it was still a summer’s day at the beach, when nothing quite satisfies like a dip — even when the ocean feels like thick, boiling syrup. Almost sticky.
“I like it hot,” shrugged Miami native Niki Candela, 20, moments after a powerful siren warned of approaching lightning.
Few of the hot people on the mostly empty beach noticed. The shore, usually clogged this year with rotting piles of seaweed, was untouched, no longer threatened by a huge sargassum patch that unexpectedly shrunk last month in the Gulf of Mexico. The shallow water was crystal teal, rolling oh so gently, no visible crested wave.
So the dauntless regulars, people who like to be warm and hate the cold, went out to enjoy themselves.
“This is as close as America gets to paradise,” said Lauren Humphreys, 40, who is originally from England but splits her time between Miami and Los Angeles. There she prefers to walk rather than swim in the Pacific Ocean, which reached about 72 degrees at the Santa Monica Pier on Tuesday.
Mrs. Humphreys made her second visit to the beaches of Key Biscayne that day, having come earlier to meditate. “There is something quite special here,” she said. “It’s peaceful.”
Off the coast of neighboring Virginia Key, measurements by the National Oceanic and Atmospheric Administration showed that the water temperature peaked at 90.5 degrees Fahrenheit on Monday, and the air temperature at 87.6 degrees. On Saturday the water temperature in that place reached 92.5 degrees, a record.
The water in South Florida is always warm this year, but unusually this year, with six record-high temperatures measured off Virginia Key this month. The sea surface hit 98 degrees in some areas of Florida Bay last week; the average ocean temperature in Miami in July is about 86.
Miami’s relentless heat this summer has meant 16 consecutive days with a heat index at or above 105 degrees, a record, according to Brian McNoldy, a senior researcher at the University of Miami. The National Weather Service predicted a heat index of 110 degrees Sunday, issuing its first extreme heat advisory for Miami-Dade County.
At the beach the next day, the burning sand was to be avoided at all costs. “Talk to me here so I don’t burn my feet,” Eduardo Valades, 51, told a reporter, motioning to the splashing water.
The water was “really warm,” he said, “but only as soon as you go in. When you get 50 meters out, it feels colder.”
“I love it,” said his wife, Jennifer Valades, 50.
The couple moved three years ago to Key Biscayne, a wealthy village of about 14,000, from California. “Here, you can literally swim for hours,” she said, though she admitted the beach was more pleasant — “perfect,” in fact — during South Florida’s mild winter, when the water temperature is more likely to be average. -70s. Coastal temperatures are also more moderate than those inland.
Ms. Valades said she recently spotted six or seven manatees. Mr Valades showed a cellphone video he recorded last month of a large shark feeding right off shore.
“We see one every three or four days,” he said, seeming unfazed by the sightings.
This week, a towel seemed unnecessary: No one felt cold leaving the water.
“It feels like a Jacuzzi!” Sasha Mishenina told her two friends after a short dip. They refused to join her.
However, a quick swim still felt refreshing, with the occasional cool current swirling and little fish darting at people’s feet.
“I’m so happy because they said we’re going to have the sargassum,” Adriana Campuzano said of predictions earlier this year, as she gathered her things to leave ahead of the looming thunderstorm. “It is clearer than it has been for years. Maybe in a decade.”
Mrs. Candela, the Miami native, came to the beach with three friends. The ocean was fine, she said, though she added that sometimes with such warm water, “you think, ‘What if someone pees in here?'”
She and her friends laid out their towels on beach chairs under an umbrella, put on some music, and invaded.
“It actually feels pretty cold,” said Taylor Dutil, 20, a fellow Florida resident.
“It’s a good change,” said Benny Perez, 22, who is from Chicago, where Lake Michigan was much cooler that day.
The siren blared three more times, signaling the end of the lightning threat. Not even rain fell. The four friends remained in the water, chatting and laughing.