By 6:30 a.m. on Independence Day, some Vineyarders were cycling uphill on North Road, already sweating in the morning heat. The temperature reached 70 degrees before seven.

Jack Hills started the day with a blueberry muffin on the Chilmark Store porch, discussing this year’s summer camp adventures. Inside, cashier Arabella Littlefields reported they were already sold out of sparklers.

Runners start the day on foot in Vineyard Haven for the annual Murdick's Run the Chop five-mile race. — Larry Glick

Dr. Lorna Andrade of Edgartown had been busy getting ready to host six guests visiting for the holiday.

“When my mother was alive, we’d host a good two dozen for the Fourth of July,” she said.

At Mocha Motts in Vineyard Haven, Bob Pozen shared a coffee at an outdoor table with Allen Sinai. The MIT professor and economist often meet to discuss the issues of the day, and on this day they said worried about the future of the nation.

“Our president thinks he’s a great negotiator, but I have my doubts,” said Mr. Pozen who said he worries about a trade war. “And I’m concerned about his treatment of immigrants. In places like MIT we can see the concerns of foreign PhD students. It’s a bad thing for our role in the world.”

Mr. Sinai said he was reading Donald Trump’s The Art of the Deal.

“I’m very concerned the country is on a downhill path in the history of the world,” he said. “The economy is really good for the short term, but I’m worried about the future.”

In Oak Bluffs, people emerged early from summer homes to drink coffee on sunlit porches and water hanging flowers. American flags drifted in the breeze.

At Inkwell Beach, the Polar Bears prepared for their ritual dip.

Renelle Roberts watched her daughter Daphney test out the water, wetting her pink water shoes.

Kevin Searle sports his festive best on Main street in Edgartown. — Ray Ewing

“She’s five and she’s super excited because she’s usually at camp during Polar Bears,” Ms. Roberts said. Ms. Roberts is an initiated Polar Bear, but she said she isn’t participating this year because she is expecting another baby in September.

She watched as her mother, stepfather and her mother in law approached the water.

“It feels wonderful to incorporate my family in something historic, and something good for health,” she said.

At about 7:30, people began to step into the sea. They formed a wide circle next to the jetty and began exercises, counting in unison. A few polar bears swam further out into the water.

Jather Crayton Jr. of Tennessee hesitated on the shore.

“I’m thinking about it, but it’s pretty cold. It’s Massachusetts,” he said.

He said his father and stepmother and aunt were all already participating.

“They come here every year,” he said. “I feel like it’s a place where they could settle.”

Before he could change his mind, he slipped off his sandals, emptied his pockets and joined the circle.

Jacquetta Van Zandt of Hyde Park was there too. She shares her birthday with the United States.

“I’ve always been a firecracker,” she said.

She has visited the Vineyard every summer since childhood, but this was her first time participating with the Polar Bears.

“It’s usually just a little too early,” she said. “But I got up this morning like I’m going to go experience the Polar Bears. It’s one of those bucket list things.”

The polar bears held hands and widened the circle. They counted off one by one, arriving at a total of 98. Thirty-nine were there for the first time. Family and friends lined the jetty, taking photos and videos of the swimmers and the sparkling water.

Twon Richardson said there is no better way to begin the Fourth of July.

“It’s the history of it, the experience of it and the unity that’s exuded during this event,” she said.

Noah Asimow contributed reporting.