The longer you are outside, the more careful you have to be to keep your family safe in the extreme heat and humidity.
Spectators were staking out their spots early Thursday for the Party on the Parkway. It's a day to display our patriotism and spend plenty of time outside with friends and family.
"I love everything about it. I love the fireworks, parades, street celebration. So I am a big fan," said Carrie Rightmare of Center City Philadelphia.
Five-year-old Julian Archer is also a big fan, and like many, his family came down early and was planning to stay late.
"We got here around 11:30 a.m. and we'll be out here all day, catch the fireworks, enjoy ourselves," said Olympia Tavorn of Drexel Hill, Pa.
But while everyone is enjoying the festivities, keep in mind as the sun beats down and humidity rises, you need to drink extra fluids which are low in sugar. And no alcohol or caffeine.
Also, take breaks in the shade like the Johnson family did under a tent. Or the Clarkes from Queens, New York, who parked themselves under a tree.
Seniors and kids are most vulnerable to heat-related problems, so keep a close eye on them.
Medics were stationed all over the Parkway area, prepared for potential problems. There were also cooling stations so everyone could enjoy a happy, healthy holiday.
And remember, if you or child has asthma, don't forget to have a rescue inhaler with you, because high humidity can make problems worse.