Lollapalooza’s opening day in Chicago was marked by significant disruptions, primarily due to extreme heat and last-minute changes to the lineup. Lorde, one of the festival’s headliners, was forced to pause her Thursday night set as audience members began to pass out from the high temperatures.

The singer, whose real name is Ella Yelich-O'Connor, observed the conditions from the stage and called for security to assist those in distress. "You look hot from up here," she reportedly told the crowd, according to Rolling Stone.

On Friday, the festival announced that headliner Lil Uzi Vert would not be performing "due to weather issues." However, the decision was reversed hours later, with Lollapalooza announcing via Instagram that the artist would indeed perform that night. Lil Uzi Vert, also known as Uzi, subsequently shared footage of himself en route to the festival, accompanied by a police escort.

Amidst the schedule uncertainties, Swedish pop star Zara Larsson’s performance was rescheduled to 6:20 p.m.

Lorde reflected on the challenging Thursday night performance in an Instagram post, describing the experience as "very out of body, doubting myself a bit, period due, dizzy in the heat." She also expressed gratitude for the festival staff and the collaborative nature of putting on such an event.

Other artists who took the stage included Suki Waterhouse, Finn Wolfhard, and Yungblud. Wolfhard, known for his role in "Stranger Things," performed music from his recent album, "Fire From The Hip." Yungblud appeared in a black leather outfit.

The festival, taking place from July 30 to August 2 in Chicago’s Grant Park, also issued a warning to attendees about intermittent rain expected throughout Friday. The forecast indicated the potential for continued inclement weather, prompting organizers to monitor conditions closely.