The UFC is telling attendees to “plan accordingly” as the D.C. region was put under a severe thunderstorm watch until 11 p.m., weather that has added a new level of uncertainty to the unprecedented championship fights scheduled to take place on the South Lawn.

“We anticipate inclement weather in the area, so attendees should plan accordingly,” the UFC announced. “We will share additional information when available.”

Capital Weather said that the “main timeframe in and around Beltway looks like 6-10 pm. Dangerous lightning, scattered wind gusts to around 70 mph, and isolated hail or a brief tornado all possible.”

Paramount+ is \planning to start its streamcast of the event starting at 8 p.m. ET. But particularly with lightning, safety is a major concern of it starting on time. Storms are fairly typical in D.C. at the end of a day of high heat and humidity.

The event is tied to the 250th anniversary of the United States, but it is also taking place on Donald Trump‘s 80th birthday. He is scheduled to arrive at the makeshift arena, constructed under a giant, Vegas-lit overhang known as “the claw,” starting at 7:45 p,m. ET, after attending a VIP reception.

Organizers said that $60 million already has been spent on the event, according to a court filing last week. About 4,000 guests are expected on the South Lawn, and tens of thousands were anticipated at a watch party on the Ellipse.

Paramount paid $7.7 billion to the rights to the UFC in a seven year deal last year. Its CEO, David Ellison, is expected to be a guest at Sunday evening’s event, per The New York Times, just two days after the Justice Department cleared its $111 billion acquisition of Warner Bros. Discovery.

The White House appears to be especially sensitive to the prospect of a rain out.

Earlier on Sunday, The Weather Channel posted on X, “UFC Freedom 250 is facing a chaotic weather setup on the White House South Lawn, with a 60% chance of thunderstorms, heavy downpours, and wind gusts up to 34 mph threatening to delay the outdoor fights. On top of the storm risk, brutal D.C. humidity is driving a triple-digit heat.”

The White House Rapid Response account replied, This event is about celebrating America’s unmatched greatness after 250 years — which apparently doesn’t sit well with the friendless loser who wrote this bullshit clickbait headline. Rain or shine, we’re celebrating our great country no matter what. GOD BLESS AMERICA!”