Hours before President Donald Trump is scheduled to participate in Washington, D.C.’s July Fourth celebrations with a rally and speech before fireworks, people are being asked to leave the event because of the weather conditions Saturday evening.

“Sorry, ladies and gentlemen, we’ve been asked to tell you, our officials have asked to tell you to, we need evacuation right away,” an overhead announcement said Saturday evening.

The “Salute to America 250 Celebration & Fireworks” celebration was slated to being in Washington, D.C., at 7 p.m. Saturday — when temperatures are set to feel like near 100 degrees, according to the forecast. However, the program was delayed and attendees were asked to temporarily leave and seek shelter in nearby buildings.

The delays forced the cancellation of some performances.

The president downplayed the intense heat in a social media post Saturday afternoon.

“Despite the heat, which isn’t as bad as predicted, the crowds in D.C. are INCREDIBLE,” he said.

The preliminary high temperature in Washington, D.C., Saturday was 102 — making it the hottest July Fourth on record for the city, according to ABC News’ meteorologists. This breaks the previous record high of 100 degrees set on July 4, 1919.

Trump told reporters on Wednesday that he won’t be deterred by the heat.

“It’s going to be approximately 107 degrees out, and I’m going to go, and I’m going to make a really long speech just to show that I can do anything,” he said.

Viewers can watch Trump’s speech live on ABC News’ website. Exact details about Trump’s planned speech have not yet been released.

The president said he will speak at 10 p.m.

Aside from the heat, ABC News’ meteorologists are also warning about dangerous storms that could hit the D.C. metro area Saturday evening — likely between 5 p.m. and 7 p.m.

A severe thunderstorm watch has been issued for parts of the mid-Atlantic, including D.C., Baltimore and Richmond, and is set to remain in effect until 10 p.m. The main concern from any severe thunderstorms that moves through is strong, potentially damaging wind gusts, which could top 60 mph in some spots.

Freedom 250 organizers said Saturday that they and their public safety partners are closely monitoring the weather in Washington, D.C., amid record heat enveloping the region. 

“The safety of our guests, performers, and staff is our top priority,” Freedom 250 Spokesperson Danielle Avalrez said in a statement, noting that they and their partners were “actively monitoring weather conditions.”

“Freedom 250 will share updates on programming — please stay close to our official channels for updates.”

Officials say they are preparing for the extreme heat and for the thousands of guests that are scheduled to attend.

Attendees will not be permitted to bring coolers into the primary secured viewing area, but officials said hydration will be available inside. Medical response plans include first-aid tents, additional ambulances, bicycle teams and multiagency response teams.

Some visitors to the Great American State Fair were treated by medics Friday because of the extreme heat. The fair had to close down temporarily Friday because of the high temperatures; the opening on Saturday was also pushed back two hours due to heat.

Extreme heat is the deadliest weather-related hazard in the United States, according to the National Weather Service.

Officials said the secured viewing area for the fireworks on the Washington Monument grounds has a capacity of approximately 150,000 people and is expected to fill early.

The event, billed as the largest display ever held over the National Mall, will feature 850,000 pyrotechnic effects and fireworks, event organizers said. The fireworks are expected to begin between 10:30 p.m. and 11 p.m. and last approximately 35 minutes, launching from 10 sites around the National Monument, Freedom 250 and D.C. officials said.

In previous years, the fireworks began around 9 p.m.

“This firework display will light up the skies over our capital as a tribute to them, and a reminder to every American watching that our greatest chapters are still ahead. It’s a moment to come together, look up, and feel proud of who we are and where we’re going,” Freedom 250 CEO Keith Krach said in a statement.

The celebration will also include several military flyovers. Ronald Reagan Washington National Airport is expected to close beginning at noon on July Fourth to accommodate the aerial demonstrations.

“The Fourth of July Airshow, over Washington, D.C., our Great Capital, will be the biggest, by far, in the History of the United States of America. Hundreds of Planes, of different types, sizes, and speeds, will be on display,” Trump said in a social media post last week.

Trump’s speech comes as Trump and his administration have faced pushback for controversial domestic and international policies. The president also faces low approval ratings — though a June Quinnipiac poll found them up from the lowest of his second term.

According to the poll, 38% of voters approve of Trump and 55% disapprove (in May it was 34% to 58%).

Quinnipiac found majorities of voters disapproved of the way that Trump is handling immigration issues, the economy, foreign policy and the ongoing war with Iran.

The president has also come under fire for several construction and renovation projects in Washington, including the demolition of the White House’s East Wing to make way for a multi-million dollar ballroom and the repainting of the Lincoln Memorial Reflecting Pool.

The Reflecting Pools has been closed off to visitors following the peeling paint and algae in the water shortly after the renovation was initially deemed complete.

ABC News’ Beatrice Peterson, Fritz Farrow and Daniel Peck contributed to this report.