LOS ANGELES - A boost in sales of foreclosures and other low-cost homes pushed the median home price in Southern California down 6 percent last month from December for the first month-to-month dip since May, a tracking firm reported Tuesday.

January's median home price in the six-county region of Southern California was $271,500, down from $289,000 in December, as higher-end home sales lost some of the momentum they had gained in recent months, San Diego-based MDA DataQuick said.

Foreclosures comprised more than 42 percent of resales last month, up from about 40 percent in December, while the percentage of sales that were in the region's lower-priced inland counties rose to more than 35 percent from December's roughly 32 percent.

"The January stats underscore just how atypical this market remains," DataQuick President John Walsh said. "Investors and first-time buyers continue to dominate many areas, while the move-up market has yet to kick in."

January's median, however, jumped about 9 percent over the year-ago median of $250,000, the second consecutive month of year-to-year increases.

Home sales crept up about 1 percent in January to around 15,400, from about 15,200 in January 2009, but sales plummeted more than 31 percent from December's 22,300, DataQuick reported.

The firm said that sales declines between December and January are normal for the season. Sales have fallen an average of about 28 percent since DataQuick began recording transactions in 1988.

January's sales were the highest total for that month since more than 18,100 homes sold in 2007, but sales were more than 14 percent below the January average of about 17,900.

"Whether significant new patterns are emerging in the market is unclear," Walsh said.

"We try not to overanalyze one month's data, and historically, January and February haven't been the best indicators for the year ahead."