WASHINGTON (AP) — Thunder and lightning delayed the start of the annual Easter egg roll at the White House on Monday, but the event eventually rolled ahead under gray skies with a large crowd including many youngsters wearing ponchos or colorful jackets against intermittent rain.

More than 40,000 people — 10,000 more than last year — were expected to attend, with children attempting to coax colorfully dyed hard-boiled eggs across the lawn to a finish line, among other “egg-tivities.” This year’s theme was “EGG-ucation,” and led by Jill Biden, a teacher for more than 30 years.

“Easter reminds us of the power of hope and renewal, and sacrifice and resurrection,” President Joe Biden told attendees, speaking from the White House balcony, where he was flanked by two large Easter bunnies, one wearing sunglasses fashioned like his trademark Ray-Bans. “But mainly love and grace towards one another.”

Biden said it’s a time to “cherish the blessings, the possibilities that we have as Americans.”

“That’s what I see in our country. We’re a great nation because we’re a good people,” he said. “Our values are solid.”

The president, accompanied by the first lady, then went down to the lawn, bending down to help a few youngsters with their eggs. He blew a whistle to officially start the roll — one of the oldest White House traditions first held in 1878.

Participants included thousands of military and veteran families, their caregivers and survivors. Members of the general public claimed tickets through an online lottery. All were being admitted in nine waves until the evening.

A large schoolhouse erected on the South Lawn offered kids activities in the fields of science, technology, engineering and mathematics, or STEM — including making circuit-breakers, simulating a fossil dig and learning about next week’s solar eclipse. Youngsters also wrote notes to U.S. troops and first responders with Operation Gratitude, a nonprofit organization.

The American Egg Board donated 64,000 eggs to the White House for the event — 40,000 for egg rolling and 24,00 for decorating and other uses.

“I’m a teacher so I love any time when we can turn the White House into a classroom,” the first lady said, noting that the South Lawn had been turned into a “learning playground and school community.”

After blowing a whistle to help with a few egg roll games, Jill Biden went to the garden outside the East Wing and read “Brown Bear, Brown Bear, What Do You See?” to a group.

The first couple also gave a brief interview Monday to NBC’s “Today” and said Easter Sunday for them featured putting dollar bills in plastic easter eggs and holding a hunt with their grandchildren. “We’re still missing one,” joked the first lady.

The Democratic president drew criticism from top conservatives and the campaign of former President Donald Trump, a Republican who is running to reclaim the White House, by proclaiming March 31 — the same day as Easter — as “Transgender Day of Visibility. ″

Asked about the criticism as he was leaving the lawn, Biden said his critics were ”thoroughly uninformed” and that he did not arrange for Easter and transgender recognition to fall on the same day.

Karine Jean-Pierre, the president’s chief spokesperson, was more direct and slammed as “cruel, hateful and dishonest” what she said was being pushed “to divide us.”

At her daily press briefing, Jean-Pierre said that “folks who understand the calendar and how it works” know that the date for Easter changes every year and that this year it coincided with Transgender Day of Visibility.

Separately, Biden was asked in the NBC News interview about his final campaign as he seeks a second term. He said he was optimistic and thinks “people are so tired of the negativity” they hear from the other side that he will be reelected.

“I think people are going to surprise people again,” Biden said.

The White House Easter Egg Roll, one of its oldest traditions, dates to the presidency of Rutherford B. Hayes, who opened the White House lawn to children after they were kicked off the grounds of the U.S. Capitol.