It's hot — but not hot enough to keep visitors away from national parks.

Especially when the admission is free.

On Sunday, the National Park Service celebrates its 103rd birthday with free entrance to sites nationwide that typically charge a fee. In California, that includes Joshua Tree National Park, Yosemite National Park and more.

To plan your trip and find information about visitors centers, camping, directions and more, visit nps.gov. Remember to pack out all trash, respect wildlife and follow other leave no trace principles.

Note: You'll still have to pay for activities like camping, transportation or special tours as they are not covered by the fee waiver.

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Last year, 28 parks nationwide reported record attendance. Overall, the National Park Service saw a drop in attendance from the record 330.8 million in 2017 to 318.2 million in 2018.

Despite the decrease, 2018 was the third-highest year for recreation visits, behind 2016 and 2017, officials said. It was the fourth consecutive year that attendance at the nation’s 418 parks topped 300 million since the National Park Service began keeping records in 1904, officials added.

“America’s national parks are national treasures that tell the story of our nation and celebrate its beauty, history and culture,” acting Secretary of the Interior David Bernhardt said in a press release.

“I am pleased that so many Americans and visitors from around the world continue to take advantage of the affordable and accessible recreational opportunities provided by these sites."

President Woodrow Wilson signed the National Park Service Act into law on Aug. 25, 1916, which established the park service.

Kristin Scharkey is features editor at The Desert Sun. Reach her at kristin.scharkey@desertsun.com or on Twitter @kscharkey. Previous reporting from Desert Sun reporter Sherry Barkas was used in this story.