The first set of athletes began competing Thursday morning at Franklin Field.
"We have some athletes here who are in two different relays and I am very excited because I am a native Philadelphian. I went to Girls High and I actually competed here," said coach Rosalind Sheppard.
It's a full circle moment for Sheppard who is now offering words of encouragement to her athletes.
"Well, just have fun. This is like the greatest track meet in America," Sheppard said.
Penn Relays is the oldest and largest track and field competition in the United States. This year, everyone will be trying to stay dry in the rainy weather.
"We didn't bring any ponchos today. We'll maybe try to run upstairs where it's covered. You're not allowed to bring umbrellas in," said Kelly Meliti of Springfield, PA.
The event is rain-or-shine and there are already a few puddles on the track.
"It is supposed to rain off and on but you got to be built for all weather. You got to run in all weather, so our kids will be ready to go," said coach Isaiah Mays.
"I think we're prepared for any outcome honestly," said athlete Ajani Landy.
The athletes say they usually aren't too worried about the weather during meets.
It's really all a blur.
"Starting off strong. Got to set the tempo," said athlete Razahn Miller.
More than 100,000 people attend Penn Relays each year.
Tickets are still available starting at $25.