In Niwot, the summer’s arrival isn’t marked by fireworks or a town-wide water balloon fight. Instead, it arrives in the slightly more sophisticated form of cymbal brushes, horn solos and Grammy-nominated jazz musicians.

From 3 — 9:30 p.m. Saturday, also the summer solstice and the longest day of the year, the town’s free, open-air Jazz Festival returns, bringing world-class musicians to a tiny town with a surprisingly big jazz soul.

The festival’s fourth rendition will bring a mix of local and national talent to Cottonwood Square, 7960 Niwot Road, Niwot, staging music genres that span from big band swing and classic jazz vocals to salsa dance.

The driving force behind the festival is Niwot resident Keith John Waters. Waters wears many hats, including bookstore owner, jazz scholar and performer. In the last few years, he added another to the stack: musical director of the Niwot Jazz Festival.

The idea for the festival came together in the wake of the pandemic, when live music opportunities had all but dried up and musicians were eager to get back onstage.

“This was right around the tail end of COVID, and musicians had really been struggling,” said Waters, a pianist, professor of music theory at the University of Colorado Boulder and co-owner of Niwot’s Inkberry Books. “There just weren’t many chances to play live, so we wanted to create something that gave local artists a way to get back out there.”

From the start, the festival was built on the simple idea of spotlighting the Front Range’s top jazz players, while bringing in a couple of national names to shake things up.

“We try to structure the festival so there’s a mix,” Waters said, “One or two national headliners, and then really strong local groups.”

It turns out that Niwot, a quirky and community-minded Colorado town, is unusually well-equipped to host a live music festival.

“You’ve probably heard of Rock & Rails on Thursday nights, or Dancing Under the Stars on Fridays,” Waters said. “There’s a culture here of live music and community events. And there are a lot of folks in town who are happy to help out, volunteer and make something like this happen.”

And though the current version of the festival is just a few years old, Niwot’s jazz legacy runs deep. A former event, Jazz on Second Avenue, ended years ago, but left a lasting impression.

“There’s been a long history of jazz festivals in Niwot,” Waters said. “This felt like a way to keep that going.”

This year’s lineup reflects Waters’ curatorial eye for range and rhythm, and it covers a lot of ground in just six and a half hours. After Midnight, a six-piece swing outfit kicks things off with a full-bodied set in the style of Benny Goodman: Heavy clarinet, tight horn sections and depression-era flair.

“That group’s a little different than some of the others we’ve had,” Waters said. “They tour all over the U.S., and they’re coming off of a big festival in Monterey.”

Up next is Angela Bingham, a Raleigh-based jazz vocalist with a sparkly edge, who, through her songs, makes listeners feel like she’s letting them in on a secret, one lyric at a time.

“People who like Ella Fitzgerald, Sarah Vaughan, or Peggy Lee, tend to love Angela,” Waters said. “She’s really out of that tradition.”

Bingham will perform with a quartet that includes Waters on piano, though her soft magnetism is likely to steal the spotlight.

Headlining the evening is Grammy Award-winning trumpeter Brian Lynch, whose résumé includes work with Art Blakey, Phil Woods and Eddie Palmieri, to name a few.

“He’s just a phenomenal player and composer,” Waters said. “And this will be the first time we’ve had a headliner descend in altitude to play in Niwot, as he’s teaching up in Aspen this summer.”

Lynch will play alongside tenor saxophonist Peter Sommer, bassist Bijoux Barbosa, drummer Todd Reid and Waters himself.

Boulder-based Quemando closes the night with a full-blast Latin and salsa set that’s almost guaranteed to get Cottonwood Square dancing.

“Their music just makes people want to move,” Waters said. “It’s pure fun, and a great way to end the night.”

If you’re the type who prefers to listen to jazz with something cold in hand, good news: the restaurants around Cottonwood Square will be open, and a fleet of food trucks will be parked nearby, ready to feed the crowd. The festival is free and fully outdoors, which sounds lovely, unless the forecast holds.

“We were joking about handing out water pistols just to help everyone stay cool,” Waters said.

And for anyone who’s not in the mood to sweat through a trumpet solo, there’s a solid backup plan: Bingham will play an indoor set at 7 p.m. Friday at nearby venue The Muse, 200 E. South Boulder Road, Lafayette.

Then on Sunday at The Muse, Lynch will bring his quintet to the candlelit stage at 7 p.m.

Still, for Waters, there’s something special about seeing it all unfold right in Niwot. Tucked neatly between Boulder and Longmont, the town is easy to get to — and once you’re there, it doesn’t feel like anywhere else.

“You can stroll through Cottonwood Square, grab a bite, and enjoy top-tier jazz for free,” Waters said. “What more could you want?”