McDonald's Corp. posted its biggest monthly increase of a key U.S. sales figure in more than a year on Monday, saying its new fruit smoothies and frappes were a hit with customers during a hot and steamy July.

In the U.S., sales at restaurants that have been opened for at least 13 months climbed 5.7 per cent — the biggest monthly increase since the world's largest hamburger chain recorded a 6.1 per cent gain in April 2009.

Overall, the measure rose seven per cent around the globe. It climbed 5.3 per cent in Europe and 10.1 per cent in the rest of the world, the company said in a statement on Monday.

The figure is considered an important gauge of a restaurant chain's performance because it excludes the effects of restaurants that open or close during the year.

McDonald's shares climbed 67 cents to $72.41 US in pre-market trading Monday. The company's stock closed Friday at $71.74 US.