All yule all the time? It’s far from a one-note arrangement

On first consideration, the prospect of filling 35 consecutive days of radio air time with nothing but holiday music seems only slightly less daunting than trying to pack Santa’s sleigh with all the toys he needs to deliver on Christmas Eve.

The reality, however, is that the difficulty confronting the programmers at KOST-FM (103.5) is in what to leave out, not what to put in.

There is a lot of Christmas music out there. For example:

* Type in “Christmas” at the music section of amazon.com and you get more than 6,000 entries.

* There are more than 500 recorded versions of just “White Christmas.”

* Johnny Mathis alone has released seven Christmas albums. So has Mannheim Steamroller.

* There have been more than 200 Christmas CDs released this year already,ranging from “Christmas With the Rat Pack,” “Soulsville Christmas,” “It’s a Tropical Christmas” and “A Very Jazzy Christmas” to albums by Ringo Starr, Harry Connick Jr., Barbara Cook, the Von Trapp Children, Hilary Duff, the Blind Boys of Alabama, Chicago, Kenny Chesney and the Wiggles.

So how does KOST decide what gets into its marathon of jingling bells, roasting chestnuts and little drumming boys?

There are three primary criteria, according to Stella Schwartz, who doubles as the station’s program director and music director.

First, this being radio, there is the format to consider. The artists and musical stylings have to be consistent with the adult contemporary music that KOST plays the other 11 months of the year. The station is programmed primarily to appeal to women in the 25-to-54 age range.

“We do not lose track of that core sound,” Schwartz says. “We offer variety, but our focus is on music by our core artists -- people like Mariah Carey, Elton John, Celine Dion, Gloria Estefan, Whitney Houston.”

That’s a pop tent large enough to include yuletide songs, old and new, by Barry Manilow, the Pointer Sisters, Air Supply, Faith Hill, Donna Summer, Kenny Rogers, Madonna, Natalie Cole, Neil Diamond, the Supremes, 98 Degrees, Linda Eder, Kenny G, Jose Feliciano, John Lennon, Bette Midler, the Beach Boys, Stevie Nicks and others -- even Bruce Springsteen with his rockin’ rendition of “Santa Claus Is Coming to Town.”

“But at the same time,” Schwartz adds, “it wouldn’t be the same without Bing Crosby and Andy Williams.”

Which is the second criterion: popularity. When KOST launched its holiday music fest in 2001, Schwartz surveyed retailers for what their bestselling Christmas discs were, and that information has been refined over the last two years with feedback from listeners.

Thus, in addition to Crosby and Williams, there is a sprinkling of holiday “golden oldies” from the likes of Nat King Cole, Gene Autry, Eartha Kitt, Burl Ives, Perry Como and Frank Sinatra.

The third stipulation is that, to attract the broadest possible audience, the holiday songs not tread too heavily into religious territory, the original meaning of the holiday notwithstanding.

“We want to just keep it the ‘holiday season’ type of thing,” Schwartz explains. “We don’t want to exclude any religions. We try to keep it generic.”

That line is a little less distinct than the others. “Joy to the World,” “Away in a Manger,” “O Holy Night,” “What Child Is This?” and “Hark the Herald Angels Sing,” for example, are on the playlist; “O Come All Ye Faithful” and “O Little Town of Bethlehem” aren’t.

Always on the lookout to expand her offerings, Schwartz says she listens to every new holiday release sent her way to see if it fits the KOST bill. Christmas recordings this year from Whitney Houston, cabaret crooner Michael Buble and “American Idol’s” Ruben Studdard, Clay Aiken and Tamyra Gray made the cut; others from Ashanti, BeBe Winans and Leon Redbone didn’t. (Don’t even ask about “The Jethro Tull Christmas Album” and “A Santa Cause: It’s a Punk Rock Christmas.”)

The station estimates that it will showcase more than 100 different performers during its holiday celebration, which began Nov. 21 and continues through 7 p.m. Christmas Day.

And yet, as Schwartz says, “So many artists, but so many recording the same songs.” Part of her job is juggling 14 versions of “Have Yourself a Merry Little Christmas,” 13 of “The Christmas Song,” eight of “Silent Night” and “White Christmas,” five of “Do You Hear What I Hear?”

“What helps is that each artist puts their own special little twist on them,” she says, “so it doesn’t sound like you’re hearing the same ones over and over.”

Whatever the difficulties of finding the right music and programming to avoid repetition, KOST’s formula works. Officials say the station had a discernible uptick in the ratings during the last two Decembers.