The cherry blossoms were so thick that they cast shadows on the grass Thursday, and the Tidal Basin teemed with visitors as the National Park Service declared Washington’s famous Japanese cherry trees at peak bloom.

The annual blossom milestone here, and around the region, came amid sublime weather, with a high of 72 and a gusty breeze rustling the white blossoms under a clear-blue sky.

It was heaven for photographers, but the concrete walkway around the basin was so congested that some with cameras had the clearest shots from the basin’s paddle boats.

“Fabulous,” Sharon Reckord, 52, of Missouri City, Tex., said as she stood beneath the trees Thursday afternoon. “Extraordinary,” commented her husband, Julius Reckord, 50.

They had seen the blossoms before, when they lived in New Jersey, they said, but had moved to Texas 21 / 2 years ago.

Cherry Blossom Parade 2014

“Being back, you appreciate it more than when we were here,” Sharon Reckord said. “You really appreciate it so much more.”

This season’s bloom is peaking at just the right moment for the culmination of the year’s National Cherry Blossom Festival. The annual Cherry Blossom Festival Parade along Constitution Avenue is scheduled for Saturday.

Park Service spokesman Brian Hall said the bloom was declared at its peak after Mary Willeford Bair, natural resource manager, inspected the trees Thursday morning and reported back.

Peak bloom is defined as the day when 70 percent of the blossoms are open. They then usually last seven to 10 days, barring high wind or heavy rain, Hall said.

There were some gusty winds Thursday, but no petals seemed to be dropping, and warm, decent weather is expected this weekend.

This year’s bloom feels late, because the average peak bloom date from 1992 through 2013 was March 31, the Park Service said. The historical average peak bloom date is April 4.

But unusually warm winters have brought peak bloom as early as March 15 in 1990. Very cold winters have pushed the peak back as late as April 18 in 1958.

In 2012, the blossoms’ centennial year, the bloom began Feb. 29, peaked March 20, and the blossoms were gone for most of the extended festival.

This year, “they are a few days’’ later than average, said Diana Mayhew, president of the festival.

“I think there’s a perception out there that they’re extremely late,” Mayhew said. “Everyone’s anxious, sick of the cold weather,” she said, and eager for Washington’s annual homage to spring.

But the bloom is “perfectly timed with the last week of the festival, and perfectly timed with the parade,” she said.

So far, the festival has been going well.

“The only disappointment that we had during the festival this year regarding the weather was the cancellation of the blossom kite festival because of three days of solid rain,” she said. “That is such a beloved tradition.”

The kite extravaganza is held on the grounds of the Washington Monument, and Mayhew said the fear was that the festivities would chew up the turf.

“Other than that, the festival has been excellent,” she said. “People have been here every weekend still, enjoying the events. . . . The city is packed right now.”

Hall, of the Park Service, said that now that peak bloom has been declared, and with the approach of the weekend, “traffic will pick up significantly.”

On Thursday, Michael Hagan, 66, a printmaker and retired government health-care economist from the Glover Park neighborhood, was scouting the scene.

He had created a striking print of a blooming cherry tree several years ago and was hunting for new ideas.

Although he has lived most of his life in the area, he said he thought this was his first visit to the blossoms at their height in decades.

“The trees, flowers, beautiful architecture, water, sunshine. . . . This basically is one of the best areas of Washington to visit,” he said.