Unseasonably cool weather failed to dampen May sales at Wal-Mart Stores Inc, which yesterday posted a 6.2 per cent increase in same-store sales - ahead of analysts' expectations and up from 3.3 per cent the month before.

For May, the nation's largest retailer said same-store sales at its Wal-Mart division rose 6.8 per cent, and increased 3.7 per cent at Sam's Club.

Total sales for the month increased 12 per cent to $18.34 billion from $16.44 billion a year earlier. Sales at the Wal-Mart division jumped 14 per cent to $11.79 billion, while sales at Sam's Club increased 9.8 per cent to $2.45 billion. Sales at the company's international division climbed 9 per cent to $2.99 billion.