The median price of an existing home in the Los Angeles region rose significantly from the year-earlier period in January and edged up slightly from December as homes sales declined sharply across Southern California, the California Association of Realtors reported Tuesday.

January’s median price of $560,740 was 17.9 percent higher than January 2005’s $475,800 and 1.4 percent higher than December’s $552,760. Sales of median-priced homes in the L.A. area plunged 23.5 percent from the year prior and 19.3 percent from December, C.A.R. said.

Statewide, the median price of an existing home jumped 13.8 percent from a year earlier and climbed a half percent to $551,300 from December’s $548,640. Sales dropped 24.1 percent from January 2005 and 5.9 percent from December.

In Orange County and San Diego County, home sales also fell, C.A.R. said. In Orange County the median price of $699,060 was 10.2 percent higher than a year ago; its sales were down 24.2 percent over a year earlier and 18 percent from December. San Diego County’s $605,600 was 4.4 percent above January 2005, and its sales dipped 20.2 percent from the year-prior period and 26.1 percent from two months ago.

Just one of the top 10 cities with the highest median home prices in California during January was in L.A. County, which was down from two cities in December: Calabasas, $1,045,000 (No. 6).

Thirty-year fixed mortgage interest rates averaged 6.15 percent during January, compared with 5.71 percent a year earlier, according to Freddie Mac. Adjustable mortgage interest rates averaged 5.17 percent last month, compared with 4.12 percent a year prior. The average number of days it took to sell a single-family home was 48 days in January, compared with 44 days for the same period a year ago, C.A.R. reported.

“The California real estate market is beginning to experience the soft landing that we expect to be the underlying dynamic driving the housing market this year,” said C.A.R. Vice President and Chief Economist Leslie Appleton-Young. “The number of homes for sale has risen to a six-month supply, which will translate into a slower rate of price appreciation than we experienced in 2005.”