A surprisingly strong rebound in California's real estate market helped lift a key home price index for the eighth month in a row.

That's good news for people who plan to sell their homes this spring. Prices are now up almost 4 percent from the bottom in May 2009, but still almost 30 percent below the May 2006 peak.

Prices rose 0.3 percent from December to January on a seasonally adjusted basis, according to the Standard & Poor's/Case-Shiller 20-city home price index released Tuesday. Among the 20 cities in the index, prices rose in 12.

The biggest monthly gain was in Los Angeles, where prices rose 1.8 percent from December. And real estate agents say there's a distinct sense that the worst of the downturn is over.

Buyers are "seeing that prices are creeping up," said Tony Middleton, a real estate agent with ZIP Realty who focuses mainly on the San Fernando Valley. "They're losing bids on homes and they have to bid again."

Prices in San Diego, meanwhile, rose by almost 0.9 percent. Phoenix had the third-largest gain at 0.8 percent.

Compared with the same month last year, the 20-city index fell just 0.7 percent from last year to a reading of 146.32. That was the smallest decline in almost three years and in line with analysts' expectations, according to Thomson Reuters.

Rising home prices also could boost consumer optimism. For most Americans, their home is their largest asset, so as values climb from the depths of the housing bust, homeowners feel wealthier and more comfortable spending. And, for homeowners who owe more on their mortgages than their properties are worth, rising prices rebuild equity.

Consumer confidence rebounded in March after a February plunge, according to a survey released Tuesday. The Conference Board's Consumer Confidence Index rose to 52.5 in March, recovering about half of the nearly 11 points it lost in February.

Still, shoppers remain cautious and there are signs that last year's housing rebound won't last. Home sales sank during the winter, and government incentives that have propped up the market are ending.

Another reason for the positive news is simply that the Case-Shiller index measures a three-month average of home prices. So January's report includes November's strong home sales.

Many analysts expect that the Case Shiller number will eventually turn downward.

"It is only a matter of time before the index records a double-dip in prices," wrote Paul Dales, U.S. economist with Capital Economics, who forecasts a 5 percent drop. The market will be tested in the second half of the year, he wrote, when a tax credit that has boosted sales is gone.

The Case-Shiller indexes measure home price increases and decreases relative to prices in January 2000. The base reading is 100; so a reading of 150 would mean that home prices increased 50 percent since the beginning of the index.