NEW YORK (Reuters) — US retail chains reported sales gains in May as warmer weather helped them rebound from a dismal April, but the results were weaker than a year ago, signalling to some that rising gas prices and a slowing housing market are taking their toll.Among retailers reporting May sales at stores open at least a year, 57 percent exceeded Wall Street expectations while 41 percent fell short, according to research firm Retail Metrics. Their overall performance was better than the firm's estimate and its long-term average — news analysts took to mean that consumer spending is holding up.

"Undoubtedly housing and gas prices are having an impact on consumers, but if you have the right product, or if you're luxury, you did fine," said Needham analyst Christine Chen.

Wal-Mart Stores Inc., the world's largest retailer, said yesterday same-store sales rose 1.1 percent in May, excluding fuel sales. Including fuel, sales rose 1.3 percent as weakness in apparel and home goods was offset by strength in lawn and garden goods, live plants and groceries.

Wal-Mart had forecast a gain of 1 percent to 2 percent.

Retail Metrics' same-store sales index averaged a gain of 3 percent in May, beating the research firm's estimate of up 2.5 percent and April's decline of 1.8 percent. But in May 2006, the index rose 4.5 percent.

"The biggest take-away is that discretionary categories remain the weakest, indicating a deteriorating consumer (everywhere except luxury), caused by high gas prices and very few apparel 'must haves'," wrote Lazard Capital analyst Todd Slater in a research note. After April sales were sapped by unusually cold weather and an early Easter holiday that pulled some apparel and candy sales into March, analysts and investors were keeping a close eye on May for signs of a slowdown in consumer spending, which accounts for roughly two-thirds of national economic activity.

"The dramatically warmer weather compelled shoppers into action and drove much stronger sales than during the month of April," said Paul Walsh, senior vice president at weather tracking firm Planalytics.

But because May is only the first month of the second quarter, and the least important month for the teen retailers — whose main "back-to-school" season starts in summer — it is premature to surmise how retailers will fare in the quarter, Chen said.

The Standard & Poor's Retail Index was down 1.4 percent in afternoon trading.

Department store operators Bon-Ton Stores Inc. Nordstrom Inc. and Saks Inc. beat Wall Street expectations, citing a host of strengths, including designer apparel and handbags.

Specialty apparel retailers that missed Wall Street expectations included Aeropostale Inc. , American Eagle Outfitters Inc. and Hot Topic Inc. . Women's retailers AnnTaylor Corp. and Chico's FAS Inc. also fell short.

Some of the chains had fashion problems with their women's apparel: American Eagle failed to capitalise on the trend of women's "baby doll" style tops; demand for AnnTaylor sweaters was off; and Aeropostale suffered weak sales of women's graphic T-shirts and capri pants.