As the weather turns warm, rock and pop stars such as Stone Temple Pilots, Third Eye Blind, Mighty Mighty Bosstones, Hanson, Christina Aguilera and Mandy Moore are firing up their tour buses to join the growing circuit of radio station-sponsored concerts.

Across the United States, stations are offering bills loaded with star power at a lower price than most summer concerts. Whether it's listener favorites playing their big hits or groups looking to boost airplay with an appearance on a daylong bill, these shows give radio stations a chance to solidify their listening community, while the musicians are able to build their fanbase.

"The advantages of doing radio shows is that we can go onstage and school the average radio listener," Mighty Mighty Bosstones singer Dicky Barrett said. "We can trick them into hearing really good music and convert the common man into a Bosstones fan." Barrett and his band played Chicago's Q101 Jamboree on Saturday along with 311, Moby, Everclear, Third Eye Blind and Travis.

One of the original radio festivals, Washington, D.C.'s WHFS HFSestival, happens again Sunday at FedEx Field. Expected to appear are Rage Against the Machine, STP, Godsmack, Cypress Hill, Deftones, Slipknot and more. A rave tent similar to that of Boston's River Rave is also planned.

"It makes radio stations look cool for putting on great concerts," said Scott Carter, senior director of product marketing at 550 Music. "And it's great for us, 'cause [our artists like] Mandy [Moore] can play to huge audiences and get major exposure."

"It's an exchange," said Michelle Gallagher, sales promotion director for San Francisco's Live 105. "We are the vehicle for the bands and they're the vehicle for us creating great entertainment for our audience."

"It may be an 'I'll scratch yours if you scratch mine' kind of thing, but I don't think of it that way," Barrett added. "We never started the band to not experience different experiences. We love to play live and that's all that we focus on whenever we agree to do any show."

A Growing Trend

Once solely limited to major markets, many of these shows began — and continue — as benefit events, according to Pollstar magazine's editor-in-chief Gary Bongiovanni. They are now also ubiquitous.

"It's gotten to the point where they've proliferated and there are multiple formats, too," Bongiovanni said. "It's not just alternative rock stations any more. And many stations are doing more than one concert per year."

Seattle's KNDD The End annually hosts summer's Endfest, scheduled this year for Aug. 5, and winter's Deck the Hall Ball. KNDD Promotions Director Franni Holman said the concerts generate enthusiastic and loyal fan response.

"We're in our ninth year of Endfest, and we start getting e-mails from listeners at the first of the year," Holman said. "It's a great branding thing for radio stations and so many bands are doing summer tours anyway, it makes sense to bring them all together."

New Economics

Reasonable ticket prices make these concerts a bonus for many fans but "tends to distort the public's perception of the cost of concert tickets," Bongiovanni said.

"A lot of times the acts only do a couple of songs anyway and you're not getting the full show by any of the acts," he noted. "But with a ticket price lower than most shows, and the star power included, it's tough for a commercial promoter to compete with that. That may explain the drop off in things like Lollapalooza."

According to Gallagher, radio festivals are becoming more like Lollapalooza, the now-defunct alternative-rock summer festival founded by Perry Farrell. "The way it's been working is the bigger they get, the more it becomes a carnivalistic scene, with different booths, rides and visual stimulation making it much more of a fun experience," she explained.

The spring and summer lineup of radio station concerts across the United States is brimming with artists working recently released albums and radio singles. The road is long — there will be at least one huge concert somewhere in America every weekend.

Summer radio concerts: