Wal-Mart ( WMT) said on Monday its June sales are on track to meet previous forecasts, as warmer weather brought customers into stores. Sales in stores open at least a year are expected to rise between 2% and 4% for the five weeks ending July 4, after the company's locations had a lackluster performance during the rainy spring season. Same-store sales at Wal-Mart stores rose at a much faster clip of 7.9% in June 2002. The company will report its monthly results on July 10. For the week ended June 27, Wal-Mart's strongest sales categories included swimwear, office supplies, toys and paint. The discount retailer also reported selling over 1 million copies of the latest Harry Potter book. Wal-Mart, the world's largest retailer, said both traffic and average spending per customer helped sales. Stores along the East Coast were the strongest. Shares of Wal-Mart lately were up 57 cents, or 1%, at $54.37.