NEWPORT — While youth was again served on Sunday at the closing day of George Wein’s Folk Festival 50, some of the old festival hands made their presence felt in the fog and rain at Fort Adams.

Judy Collins, Joan Baez and bluegrass legend Del McCoury, who all made their Newport debuts in the early ’60s, as well as veterans Guy Clark and Arlo Guthrie, held stage alongside the younger rock-influenced performers.

While the show ended with another sing-along led by folk icon Pete Seeger, his grandson, Tao Rodriguez-Seeger and his band, and many of the day’s acts, Collins provided the introduction, with her voice of icy perfection still hitting great heights during such hits as “Both Sides Now,” and keeping the rained-on audience of 7,800 entranced during the expansive story song “The Blizzard” and finishing up with a duet with Baez on “Diamonds and Rust.”

Baez may have lost a bit of the top of her range, as she acknowledged during her set, but there was still enough guts and glamour to bring the emotion to favorites such as “Forever Young” and “Farewell Angelina,” along with an a capella encore of “Oh Come Angel Band,” all of which (except for the latter, of course) made more affecting by her acoustic band.

Guthrie spun his traditional charming web of song and story, his introduction to “I Don’t Want a Pickle” recounting the creation of the song (“What the hell kind of song is this?,” he asked himself) and an unfortunate biker who made two trips to the emergency room in one day (don’t ask) and taking longer than the song itself.

Providence-based Deer Tick exploded onto the third stage, with guitarist and singer John McCauley announcing their presence by declaring, “Once you plug in an acoustic guitar, it’s an electric guitar, so let’s skip the song and dance.” They then tore into “Easy,” with McCauley’s greasy drawl nicely undercutting the sugar of the melody. McCauley and the band (bassist Chris Ryan, drummer Dennis Ryan and guitarist Andrew Tobiassen) continued raucously through “Little White Lies,” eventually pulling back for a hushed “Song About a Man.”

With stops along the way for a John Prine cover (“Unwed Fathers”) and a guest appearance by Liz Isenberg on “Friday XIII,” they finished with the roots-rock of “Straight Into a Storm” and an uproarious “La Bamba,” all of which torched the overflow hometown crowd.

Tobiassen said later that last year he was an usher at the backstage tent “checking to make sure everyone had the right pass. Now I’ve got the right pass,” he said with a smile on his way in.

In the morning, Gillian Welch and North Smithfield native David Rawlings cut their usual figure (Welch hunched over her guitar in concentration, Rawlings twisting his toward the microphone) as they put lovely, classic Americana touches on songs such as “Queen Jane Approximately” and “Jackson,” while The Campbell Brothers upheld the sacred-steel tradition by tearing through “The Judgment” with screeching slide guitars and popping bass that brought the Old Testament thunder.

While Guy Clark sang that he was “tired of the same old lines” on the second stage, Chicago singer-songwriter Joe Pug was doing something about it on the third stage, occasionally Dylanesque in his exterior trappings and opaque in his poetics, but also touching and foreboding on songs such as “I Do My Father’s Drugs.”

Indie-rockers Elvis Perkins in Dearland capped off the second stage with a heavy traditional element to their mix, with gospel-style vocals on “Weeping Mary,” and incorporating some of the shape-note singers from Tim Eriksen’s group for “Four Strong Winds” before finishing with a rolling, tumbling “Doomsday” that saw three members of the band pick up horns, and drummer Nick Kinsey a marching bass drum.

As with Saturday, Seeger seemed to draw more energy from leading a sing-along than he did from performing himself. “If there is a human race in 100 years,” he said Saturday, “[they] will find how important a word, in any language, is ‘participation.’ ”

His grandson agreed, saying Saturday that “the human connection through music” was paramount to the folk legend. It also helped him deal with fame, which Rodriguez-Seeger said his grandfather finds “a slightly maddening condition. … If anything, it’s an impediment to life. However, you can move masses.” If people are going to make the retiring Seeger into a star, his grandson said, then Seeger would use that influence: “I’m gonna rope you into my thing.”

It’s becoming old hat to say Newport stretches the folk tradition, but after the weekend the old saying can be reversed: I can’t tell you what it isn’t, but I can tell you what it is:

It’s Ben Knox Miller, of the Providence-based Low Anthem (who played Saturday) listening to Deer Tick while bandmate Jeff Prystowsky was awed by Guthrie.

It’s the members of Dearland, who were all over the festival all weekend, soaking in the range of music, Kinsey later acknowledging that “It’s totally mind-blowing for us to be at a festival we’ve all known about all our lives” before going off to sing along with Seeger.

Or, as Collins said in a news conference before going on, “The folk tradition gets renewed every time someone writes a good song.”

rmassimo@projo.com