BENTONVILLE, Ark.- Wal-Mart Stores Inc.'s same-store sales rose 6.2 percent last month, more than the world's largest retailer had forecast, as it gained sales at the expense of department stores and grocery chains.

The retailer said yesterday that sales in the four weeks that ended Friday rose 12 percent to $18.34 billion. Last month, Wal-Mart forecast a 4 percent to 6 percent rise in sales at stores open at least a year.

Sales of seasonal items such as gardening equipment and summer clothing rose over the Memorial Day holiday as temperatures rose after falling below average in the first three weeks of the month, analysts said. Discount chains such as Wal-Mart and Target Corp. are benefiting the most as consumers continue to control their spending as the economy improves.

"When bad weather hits, Wal-Mart will look that much better than the rest of the industry," said Ken Wong of Roger Engemann & Associates, which has about 2.65 million Wal-Mart shares as part of about $8 billion in assets under management. "They just have a bigger part of their business in categories like food and consumables that aren't as affected."

The retailer's results are expected to lift U.S. same-store sales for last month. Sales at stores open at least a year are expected to have risen about 3.5 percent, more than a 2.5 percent forecast last week, according to the Bank of Tokyo-Mitsubishi.

Shares of Wal-Mart rose 96 cents to $54.96 yesterday. They are down 4.5 percent this year.