Dancing under a Chicago summer sun, packed into a crowd close to a stage with little room for air will sneak up on you fast.
"It kind of just went white and I couldn't really see much or hear much. I'm not really sure what happened," said Liam Whan, concertgoer.
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Whan's heatstroke was a common sight in the sea of more than 100,000 people.
"We were in line for like an hour and probably saw four or five people pass out and, like, 10 people throw up," said Ethan Diacondscu, concertgoer.
"Probably every 30 seconds someone was getting pulled out," said Xavier Gastelum, concertgoer.
Friday temperatures along the lakefront never even hit 80.
"The best is to stay by the railing so you can get some fresh air because you're not smelling sweat the entire time," said Jocelyn Jurado, attendee.
Saturday, with temperatures in the 90s expected to blanket the festival, it could be brutal.
"Tomorrow shorts, lots of water, try to stay in the shade and take breaks as much as I can," Gastelum said.
Hydration stations scattered all over Grant Park make the access to water easy; concertgoers just have to bring their own bottles and the refresher is free.
The hydration stations and spots in the shade may be as popular as the headlining acts this weekend.
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