Along with the music and food at Riverbend comes the heat. Temperatures usually hover around 90° when the gates open each afternoon, although it can feel hotter.
"When the humidity is at a certain level, the way your body cools itself is by evaporation of perspiration," explains Sylvester.
So far in 2017 the hottest it's been is 93° which has happened twice through Thursday. In 2016 highs reached warmer than 93° six of the nine days during the festival. If you don't stay hydrated, your body will have a tougher time cooling down.
Sylvester recommends drinking water before coming to the festival, then drink more from time to time throughout the evening, especially if you're also planning to drink beer.
"If they alternate it or maybe two to one, at least, and maybe throw a Gatorade in there it'll really offset the problems it causes," says Sylvester.
If you don't want want to be among the dozen or so people treated for heat exhaustion each night, also remember to wear light-colored, loose-fitting clothing. Shorts and tank tops work best, allowing for good air circulation. If something does happen, EMS is here to help with two treatment tents set up.
"One is down by the Olgiati Bridge, and one is on Chestnut near the main entrance," says Sylvester. "But we also utilize rolling crews. We have riving teams of medics that go through the venue."
Free bottled water will also available at the tents. If you can, find a cool spot in between acts. That's Mike Patterson's plan. He's here from St. Louis.
"We're staying right down the street at a hotel. So if it gets too hot we'll go in. It's not bothering us too much yet," says Patterson.
Sylvester says the weather is something that goes along with Riverbend. You just have to be prepared.
"Every year it seems like the heat of the summer hits right about the same time as the Riverbend festival. It's kind of a tradition just as much as the festival is," adds Sylvester.
You're probably going to be walking a lot. Sylvester also suggests wearing comfortable footwear, but avoid flip-flops or brand new shoes. Foot injuries and blisters are also treated frequently by EMS during Riverbend.