Occupancy rates in Aspen and Snowmass Village plunged by double digits in December compared to 2011, according to figures released by the Mountain Travel Research Program (MTRiP).

While occupancy in Aspen dipped 15 percent for the month, average room rates rose from $498 in December 2011 to $582 last month, or nearly 17 percent.

In Snowmass Village, occupancy was down 12.5 percent, and the average room rate increased about 10 percent, from $347 in 2011 to $383 in 2012, according to figures from MTRiP. The organization tracks occupancy at 16 western destinations.

“I would observe that this was primarily a function of strong bookings during the last week of December when rates were high, but very weak bookings during the first half of the month when rates were low,” wrote Bill Tomcich, president of central reservations agency Stay Aspen Snowmass, in an email.

December saw an overall occupancy rate of about 48 percent, compared to 56 percent for the month in 2011. Snowmass Village fell to 36 percent for the month versus 41 percent in 2011.

An “impressively strong and extended” New Year’s weekend pushed occupancies in excess of 90 percent in both towns, Tomcich wrote.

His email says that Stay Aspen Snowmass experienced a couple of “extraordinary booking weeks in late December that coincided with Mother Nature being really generous to our resorts.”

As of Dec. 31, occupancies for 2012 in Aspen and Snowmass Village were trending down very slightly from the previous year, Tomcich wrote.

“But it must be kept in mind that these comparisons are against one of our strongest January’s ever,” he wrote of 2012.

The Wintersköl weekend, Gay Ski Week and the Martin Luther King Jr. weekend should all help boost occupancy, though there will be a “very brief trough” on Jan. 21-22 when occupancies drop below 60 percent, according to Tomcich.

Occupancy rates are expected to peak for the Winter X Games the following weekend.

“All that said, we should all be quite pleased with how January is shaping up,” Tomcich wrote.