Download: S&P/Case-Shiller Home Price Indices, first quarter

The nation’s housing markets are weakening, but San Diego’s prices are strengthening at an accelerated clip, the widely watched Standard & Poor’s/Case-Shiller Home Price Index showed Tuesday.

The index for San Diego, based on a three-month rolling average price for the same single-family home over time, has risen 11 straight months, even as the composite index for 20 metro areas declined for the sixth straight month.

For March, San Diego’s index was up 1.5 percent from February and 10.8 percent from March 2009, but the 20-metro index was down .5 percent from February and 2.4 percent from a year earlier. The rate of the San Diego monthly increase has grown each month from .2 percent in December; the year-over-year increase has risen rapidly from .4 percent in November.

S&P’s index chairman, David M. Blitzer, said the nation’s housing market is in better shape than at this time last year.

“But when you look at recent trends, there are signs of some renewed weakening in home prices,” Blitzer said.

He said with the April 30 expiration of federal homebuyer tax credits, demand may sag.

The report said Los Angeles , Minneapolis and San Francisco , as well as San Diego, have all recovered from their recent lows.

“San Diego, in particular, has stood out with 11 consecutive months of increasing prices,” the report said.

In a breakdown of the San Diego market, the top third of housing, priced over $465,686, did the best in March, up 2.9 percent from February and 7.7 percent from March 2009. The bottom tier, below $311,200, was down .3 percent from February but up 11.3 percent year over year. The middle tier was up .6 percent from February and 7.2 percent from March 2009.