NEW YORK (CNNMoney.com) - Mother's Day sales, warmer weather and the right summer fashions helped some retailers post solid sales last month despite high gas prices.

Among the retailers who reported May sales Thursday at their stores open at least a year, a key retail measure called same-store sales, a few specialty apparel sellers logged robust numbers that trounced analysts' estimates for the month.

But some big chains, Wal-Mart among them, turned in far weaker performances.

Trendy clothier Guess (Research) saw sales surge 20 percent in May versus analysts' expectations for an 11.3 percent increase, according to Thomson Financial. Teen apparel seller American Eagle Outfitters (Research) posted sales that jumped 11 percent last month.

Limited Brands (Research), the operator of Victoria's Secret, Express and Bath & Body Works chains, posted a 7 percent sales gain. Analysts had expected a 5.3 percent increase. Among the department stores, high-end seller Nordstrom (Research) reported same-store sales up 7.8 percent.

There were some disappointments, however.

Sales at the Goth and music-inspired clothing merchant Hot Topic (Research) fell 6 percent last month. Industry watchers say Hot Topic's concept has suffered because of the current apparel fashion cycle, which skews toward more colorful and preppy looks for teens.

And beleaguered home furnishing retailer Pier 1 Imports (Research) posted a 6.6 percent drop in May sales.

"The numbers this morning are not too bad," said Ken Perkins, president of research firm Retail Metrics. "The late spring, early summer merchandise appears to have resonated with consumers. Mother's Day sales and warmer weather in the later half of the month certainly gave a lift to sales."

Another winner was wholesale club operator Costco (Research), which posted a 10 percent same-store sales increase well ahead of analysts' forecasts of a 7.3 percent gain. Given that the discounters are the most exposed to higher gas prices, Perkins said Costco's better-than-expected numbers were a nice surprise.

But discounter Wal-Mart (Research) didn't fare as well. The world's largest retailer posted May sales that rose 2.3 percent, at the low-end of its forecast for a 2 to 4 percent gain. Moreover, the company said it expects June same-stores sales to rise between 1 to 3 percent but cautioned that high energy prices are weighing on consumer spending.

Many economists look to Wal-Mart as a barometer of consumer spending power given its status as the world's largest retailer, averaging more than 100 million shoppers a week.

So how troubling is Wal-Mart's warning about the gas price pressure on its core low-to-mid income clientele?

Michael Englund, chief economist with Action Economics, agreed that discounters are disproportionately impacted by gas price fluctuations. "But as long as the savings rate is low and consumers are continuing to spend elsewhere, we'll still see cash flow through the economy," Englund said.

Further, Perkins said a relatively strong job market and wage growth should provide support to consumer spending in the months ahead, helping to offset the headwinds of higher interest rates and a cooling housing market.

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