San Diego home prices did a funny thing in late winter. They stabilized.

Median home prices were unchanged at $285,000 in February and March, even as sales volume increased, according to MDA DataQuick, a La Jolla-based research firm.

Analysts caution there is still a glut of unsold foreclosures that banks have yet to list for sale, which is likely to keep prices low.

Also, so-called jumbo loans, or loans greater than $417,000, have yet to return, leaving many buyers unable to shop in more expensive neighborhoods.

Homes in older, more costly neighborhoods have come down in value by half as much as homes in newer, more affordable neighborhoods, said DataQuick president John Walsh.

San Diego saw 3,020 new and existing homes sold in March, a big jump from 2,473 sales in February and 2,108 sales in March 2008.

DataQuick spokesman Andrew LePage said there are usually seasonal increases between February and March.

“Nothing unusual about that — you’re just starting to pull out of the winter/holiday doldrums,” he said.

Foreclosure activity in San Diego increased in March, according to ForeclosureRadar.com, which is based in Northern California.

There were 3,892 notices of default sent in March, the first step in the foreclosure process; another 2,499 notices of trustee sales were sent and 662 properties sold at auction.

That’s up from February, which saw 3,353 notices of default, 1,443 notices of trustee sales. Some 1,276 properties sold at auction.

“I expect in general many starts and stops, and foreclosures are likely to go up before they peak,” said Norm Miller with the University of San Diego Burnham-Moores Center for Real Estate. “There is an awful lot of lender inventory being held out of the market.”

DataQuick will release first quarter statistics on San Diego foreclosure sales the week of April 20.