This year, there will be some big changes to the event. Vendors will be selling marijuana products, so the gathering will be fenced off and limited to adults only.
"Because this is the year where there are legal sales, state law requires that you will not be allowed in unless you are 21," said Phil Ginsburg, general manager of the San Francisco Recreation and Parks Department.
Ginsburg says officials will be checking IDs and there will be park rangers, security guards, and police on hand.
"Our goal was to try to make it as safe as possible," said GInsburg.
For some people, the grass is always greener at Hippie Hill on 420. Tens of thousands of people have come to Golden Gate Park in years past.
"I think everyone's going to come out and have a good time," said Savannah Vines, a Concord resident who was enjoying the sunshine with friends sitting on Hippie Hill Tuesday as organizers set up for the event.
Community organizers spent all day setting up the main stage and tents for more than 40 sponsors, merchant booths, and food trucks. Also new this year will be two VIP platforms for better viewing of the performances.
Alex Aquino, the organizer and founder of Sounds Bazaar events, says this year will feature a special comedy tribute to Robin Williams.
"They renamed this meadow Robin Williams Meadow, so we're doing a dedication to him in honor," said Aquino, "We have comedians. We have Jeff Ross and Hanibal Buress."
The Goldman Tennis Center nearby will be closed all day. The Koret Children's Playground which is right behind the main stage will also be closed.
Some long-time residents say they're glad to see the city step in with organizers to keep the peace.
"Some years it's been a complete cattle call over here with people just not necessarily lawless,"I mean everybody just gets stoned and stupid quite frankly," said Joshua Jennings of San Francisco, "I think it's a great idea that they're going to be putting some structure to it."
Others say making 420 a formal event changes the feel.
"This organized, fenced-in gathering is a little bit more commercial than...what cannabis meant for people in the community," said Malarie Parks, who says she's traveled from Mammoth Lakes to attend the 420 gathering twice before the pandemic.
San Francisco Recreation and Parks staff said that in the years before the event was officially recognized, the park staff and neighbors faced problems with parking, sanitation, and trash.
"For years, people left this place a dump and it was really depressing," said Ginsburg, adding that his crews often spent days cleaning up afterwards.
The city's message to attendees this year is simple.
"Be respectful of this very special park. Treat it like its yours. Be kind to the neighborhood and be considerate to each other," said Ginsburg.
Some details to remember include:
*Large coolers, tents, and pets are banned.
*Gates open at 10 a.m. Performances are scheduled from 12 noon to 5 p.m. with the event ending at 6 p.m.
*Express shuttle bus service - SF Muni will run a special express shuttle bus pickup from 4p.m. to 7p.m. that will take people from Hippie Hill to the Civic Center where they can catch BART or a bus home.
Jana Katsuyama is a reporter for KTVU. Email Jana at email@example.com and follow her on Twitter @JanaKTVU or Facebook @NewsJana or ktvu.com.