Thunder rumbled and rain pelted on the roof of the South Shore Music Circus tent on Wednesday, June 14, but concert-goers left the venue “happy together” all the way home.

For the 14th straight year under the Cohasset big top, the Happy Together Tour featured original members of the Turtles, Little Anthony, Gary Puckett and the Union Gap, the Association, The Vogues, the Classics IV and the Cowsills, who filled the outdoor tent with the songs that smashed the Billboard Top 40 charts in the sixties and seventies.

The musicians, some of them founding members of the groups that made them famous, wore tie-dyed shirts, dress suits, sequined jackets, and a Civil War uniform. The performers—many of them in their seventies and eighties—had hair that was whiter and moves that were slower, but their voices and instruments were rich and resonant enough to bring their baby boomer fans back to a simpler time when they were “feeling groovy.”

The Cowsills kicked off the concert with some of their favorite hits of the sixties, including “Hair” and “I Love the Flower Girls.” Susan Cowsill 64, the baby of the night, was dressed in hot pants and fishnet stockings and looked like the free-love hippie she once was.

Original Turtles member Mark Volman, 76, dressed in a multi-color Charlie Brown and Snoopy vest, was joined for the tour by Ron Dante, 77, former lead singer of the cartoon rock band, “The Archies.” Dante performed his own hits, “Sugar Sugar” and “Tracy,” and Volman roused the crowd with his audience-participating rendition of “It Ain’t Me, Babe.”

Wearing a blue, sequined dinner jacket, Jerome Anthony Gourdine, whose group, Little Anthony and the Imperials, was inducted into the 2009 Rock and Roll Hall of Fame, had his falsetto voice intact on the Cohasset stage as he thrilled the audience with his fancy footwork at a spry and cheerful 82 years old. Gourdine performed “Tears on My Pillow,” Going out of My Head,” “Hurts so Bad,” and joked about one of his group’s biggest hit records, “Shimmy, Shimmy, Ko-Ko-Bop.” “I never really liked that song when we released it,” he said. “But it sold a million records, so I guess you all did.”

A lean and long-haired Gary Puckett, 80, took the stage wearing a Union Soldier’s green uniform, as his group had done in its heyday. He performed a roster of hits, including his once controversial song, “Young Girl” and the ever-popular “This Girl is a Woman Now,” which brought cheers from the crowd.

The three members of the Vogues were comics as well as singers during their on-stage banter with their fans. Dressed in matching purple paisley button-down shirts, they sang their signature hits, “Five O’Clock World,” “You’re the One,” and “My Special Angel” while the audience sang along.

“This was a fabulous throwback night for me and my husband,” said Roberta Engler, 72, of Marshfield. “We danced to all of these songs in high school, and we played them at our wedding. Whenever these guys come to Cohasset, we’ll be there.”

Allison Kieffner, 43, of Norwell was among the youngest fans at the Music Circus for the Happy Together tour. “My mom and dad always listened to oldies when I was a kid, and my brother and I both got into them,” she said. “I love watching YouTube videos of these groups from the sixties and seventies. It’s unbelievable that they can still perform like this 50 years later.”

For one patron, The Classics IV’s rousing reprise of its megahit, “Spooky,” was the highlight of the show. “That amazing saxophone solo by Paul Weddle honestly gave me the chills,” said Al Fricker, 73, of Scituate, who wore an “Old Guys Rule” T-shirt to the concert. “It sounded just as great as it did when they released that record in 1967. I loved it as a teenager, and I loved it tonight.”