The Christmas party is over at KOST-FM

The flashing lights, inflatable Santas and desiccated Christmas trees have all come down, and so have the gaudy ratings numbers for KOST-FM (103.5) — annual home of nonstop holiday music.

Once Christmas was over, KOST returned to its normal playlist of adult-contemporary music and dropped from first to second in the January ratings, according to figures released this week by the Arbitron ratings service.

The station — which every year since 2001 has converted to constant carols for the holidays and seen a subsequent bump in its popularity — claimed an astonishing 9.3% of the Los Angeles-Orange County audience during 2010’s final ratings survey. But come January, KOST’s audience share fell to 5% of listeners ages 6 and older.

Meanwhile, Top 40 station KIIS-FM (102.7) regained its perch as the market’s most popular outlet, the spot it had occupied from January to November 2010 — right up until the Christmas carols started playing at KOST.

KIIS increased its average share of audience from 5.4% during the holidays, when it finished second, to 5.7% in January.

Arbitron divides the year into 13 four-week ratings periods, one for each month plus a year-end “holiday” period. The January 2011 ratings surveyed listeners from Jan. 6 to Feb. 2, while the holiday period recorded their preferences from Dec. 9 to Jan. 5.

In January, pop station KAMP-FM (97.1) increased its average weekly audience from the holiday timeframe, rising from 3.13 million to 3.18 million listeners who tuned in for at least five minutes each week. But, amid the jockeying by the stations, KAMP actually dropped from fourth to a sixth-place tie, as its share of the total audience fell from 4% to 3.5%, the same as hip-hop station KPWR-FM (105.9).

Oldies station KRTH-FM (101.1) maintained third place from the holidays to January, increasing slightly from 4.3% to 4.4%. Talk station KFI-AM (640) rose from seventh to fourth, taking 4.1% of the audience. Spanish-language pop station KLVE-FM (107.5) was fifth, rising from 3.5% to 3.9%.

Normality returned to morning radio, as well, as KFI reclaimed its usual place at the top of the heap from 6 to 10 a.m. weekdays.

KFI, which airs local host Bill Handel and then the first hour of Rush Limbaugh’s syndicated program during that time frame, claimed 5.8% of the listening audience. Tying for second, at 5.3%, were Ryan Seacrest on KIIS and the team of Kevin Ryder and Gene “Bean” Baxter on alternative KROQ-FM (106.7). KOST, which had been No. 1 during the holidays, fell to a sixth-place tie, as the station’s Mark Wallengren and Kristin Cruz garnered 4% of the morning audience, the same as Gary Bryan on KRTH.

calendar@latimes.com