Peak bloom for Washington's famed cherry blossoms will be March 26 to March 30, the National Park Service announced Monday.

"Seventy percent of the blooms will be out during that time," National Park Service spokeswoman Carol Johnson said. "Though there's an awful lot of variability."

This year's peak is expected to be later than last year's, when warm temperatures had the blossoms in full force as early as March 20. The average peak bloom date is April 4, according to the National Cherry Blossom Festival's website.

The weather in the next few weeks will determine the exact bloom dates -- colder weather means a later bloom time, while warmer weather will bring out the blossoms earlier, Johnson said.

"The big thing that we cannot predict is how long they'll be open," she added. "Snow or rain can knock the blossoms off."

The expected bloom would coincide with this year's National Cherry Blossom Festival, which is scheduled for March 20 to April 14. The festival, which commemorates the 101st anniversary of Japan's gift of cherry blossom trees to the United States, is expecting 1.2 million attendees. That's down from about 1.5 million last year, though the centennial celebration was nearly two weeks longer.

Festival spokeswoman Danielle Piacente said that peak bloom almost always occurs within the festival dates, though that's partly because the even lasts for weeks.

"Last year they bloomed early, but that wasn't a problem," she said. "It's nice when it coincides, but it's not something that's make or break for us."

The expected bloom will also coincide with spring break for many school systems, since Easter is March 31.

Festival officials aren't the only ones preparing -- Metro is planning to halt construction almost completely during the festival to ensure full service for the estimated one million tourists who descend on Washington each year to see the trees. The only planned track work will be done late Sunday nights, according to a Metro release.

John Malott, president of the Japan-America Society of Washington DC, said that the blossoms offer residents and visitors a link to the history of both the District and Japan.

"Of the 3,000 trees they gave us, I think about 140 of the original trees are still alive," he said. "It's remarkable considering that the variety that we have has a lifespan of about 60 years."

Malott added that different varieties of trees and different temperatures around the region mean that not all trees will be blooming at the same time. Still, he said, nothing beats seeing the circle of trees in bloom at the Tidal Basin.

"What makes our trees unique is the location," Malott said. "You can stand there anywhere on the Tidal Basin and everywhere you look you see cherry blossoms."