Post holidays, KOST-FM drops, KIIS rises to top Radio listeners who had flocked to the all-holiday music format on KOST-FM (103.5) during the Christmas season just as quickly retreated to their regular stations once the last "Jingle Bells" and "Little Drummer Boy" had been played. That meant a return to the ratings pinnacle in January for pop station KIIS-FM (102.7), according to figures released by the Arbitron ratings service. KIIS, mirroring the Top-40 hits on its playlist, was the most popular station in the Los Angeles-Orange County market for most of 2012, until KOST began its annual holiday music festival in mid-November. And it reclaimed that crown last month, grabbing 5.7% of the listening audience age 6 or older. KOST, which ceased its nonstop seasonal music on Dec. 26, slipped to third place, based on the survey of listeners from Jan. 3 to Jan. 30. PHOTOS: Celebrity portraits by the Times Even so, in some ways KOST fared better than it did at the same time last year, or last fall, before it made the switch to all-holiday music on Nov. 15. Arbitron divides the year into 13 four-week ratings periods, one named for each month plus a year-end holiday period. KOST routinely dominates the December and holiday time frames with its switch to carols from its usual playlist of adult-contemporary hits. Although a decline is inevitable, the station hopes to retain as many of its seasonal listeners as possible after its return to regular programming. This year KOST had a long way to fall: Its 10.2% audience share in the holiday book was the highest rating for any station since the end of 2008, when Arbitron expanded beyond releasing only quarterly ratings. KOST boasted a holiday audience of 4.56 million - the number of individuals who tuned into the station for at least five minutes in the average week. In 2012, KOST held on to enough of its listeners to retain the top spot in January, tying with talk station KFI-AM (640). It did so with a 4.8% share of the audience and a weekly audience of 3.23 million listeners - totals that the station exceeded this January, even though it placed third overall. In January 2013, it snagged a 5.3% audience share and 3.33 million listeners. This past month KOST also exceeded its marks from November 2012, its last full ratings book before switching to Christmas music on Nov. 15. In that November ratings period, which ended before the music switch, KOST placed fourth, with at 4.3% audience share and 3 million listeners. KTWV-FM (94.7), the smooth-jazz and adult-contemporary station known as "The Wave," also switched to full time Christmas music from Nov. 15 to Dec. 26, the second year in a row it tried the tactic. It placed fourth, at 4%, during holiday 2012 and fell back to 2.8% in January, tied for 14th place with all-news station KNX-AM (1070) and country station KKGO-FM (105.1). The previous year, KTWV scored a 3.7% share for sixth place in holiday 2011 and slipped to 3.2% and 11th place the following month - so its holiday offerings were better received this year, but its fall back to earth was a little steeper in January 2013 than in 2012. Also last month - for only the fourth time in four years - morning-radio listeners chose a different No. 1 station. In weekday morning drive, the highly competitive 6-10 a.m. slot when stations try to grab listeners and hold them for the rest of the day, KFI has long dominated. Its lineup of local host Bill Handel and the first hour of Rush Limbaugh's national program kept competitors far behind. The only exceptions were when KOST and its Christmas music leapt ahead during the holiday periods in 2010 and 2012, and in March 2011, when alternative rock station KROQ-FM (106.7) beat KFI, 6.2% to 5.9%. But last month, KIIS' Ryan Seacrest and his co-host, Ellen K, took the top spot with 5.5% of the audience, with KROQ and its duo of Kevin Ryder and Gene "Bean" Baxter right behind at 5.4%. KFI came in at 5.3% - very close behind but in a very unfamiliar third place. KOST, and its morning team of Mark Wallengren and Kristin Cruz, dropped back to fourth at 4.5%, after taking the top spot during the holidays.