Pop-music lovers used to have to wait until the last quarter of the year for blockbuster album releases — just in time for holiday gift-buying.

But the lagging economy has sharpened year-round competition for entertainment dollars, prompting artists and record labels to seek a wider window for marketing their wares.

Summer has become the second season for CDs.

"Late spring and early summer have become a pretty big hotbed," says Brian Faber, general manager of the Arizona-based Zia Records chain.

Such music-centric Web sites as Pause&Play and Pitchfork list hundreds of CDs hitting store shelves or about to go on sale in the summertime, by artists ranging from such big acts as Green Day, Eminem, the Jonas Brothers, Brad Paisley and Ciara to indie outfits like the Eels, Iron & Wine, the Mars Volta and Jeremy Enigk.

Green Day recently released "21st Century Breakdown," its first studio album in five years. Eminem's "Relapse" marks the end of a four-year hiatus. Rapper Lil Wayne dips into rock with "Rebirth." The Black Eyed Peas regroup after Fergie's solo projects with "The E.N.D.," and the Dave Matthews Band rebounds from co-founder LeRoi Moore's death with "Big Whiskey and the Groogrux King."

Other high-profile releases include Elvis Costello's "Secret, Profane & Sugarcane," Paisley's "American Saturday Night," Ciara's "Fantasy Ride," Rob Thomas' "Cradlesong," Tori Amos' "Abnormally Attracted to Sin," Busta Rhymes' "Back on My B.S." and Mandy Moore's "Amanda Leigh."

The summer-CD trend eases the holiday-sales glut that is a huge headache for retailers.

"If everyone tries to come in the fourth quarter — and retailers hate that — we're all competing for the same dollars, and not everyone can win," says Jim Roppo, a sales executive for Island Def Jam Music Group.

Adding summertime to the equation allows retailers to put the spotlight on more albums.

"It seems to generate more of a following (for each CD) from customers," says Josh Byrd, a media supervisor for Best Buy in Phoenix.

"If three or four of their favorite artists are releasing albums, it's better to have them spaced out."

Zia's Faber adds that summer is a time when people tend to spend money on themselves, rather than on holiday gifts, opening up a new area of demand.

Also pushing more releases into summer this year is a change in the deadline for music to be eligible for next year's Grammy Awards. The deadline has been pushed up 30 days, to Aug. 31.

"In September (in years past), there had been a flush of releases that came out from the biggest artists and some of the more eccentric ones to make sure they were in for Grammy consideration," Roppo says. "Now, that will happen in August."

An economic double-whammy — the recession coupled with the continuing slip of CD sales due to the popularity of singles purchased online — has magnified the need to entice record buyers in both winter and summer, Roppo says.

"We're affected by the overall economic picture. While music is a low-cost entry point for entertainment, people are spending less on discretionary items."

The changing pop-music landscape has flipped another time-honored summertime tradition: Many pop-music acts now earn more through ticket and merchandise sales tied to concerts than they do through CD sales, says Mark Goldstein, a professor in the Thornton School of Music at University of Southern California.

So while summer concert tours used to be a means of marketing albums, he says, a CD release now is apt to be used to generate interest in a band's profitable live shows.

"It's not so much about music these days as it is about marketing," Goldstein says.