NEW YORK — McDonald’s is fighting to hold onto customers in the U.S. — and all that snow didn’t help.

The world’s biggest hamburger chain said Monday that sales fell 1.4 percent in February at established U.S. locations. It blamed the harsh winter weather, but conceded that “challenging industry dynamics” also played a role.

After years of outperforming its rivals, McDonald’s has been struggling to boost sales as people flock to places like Chipotle and Five Guys Burgers and Fries. Those chains have popped up quickly by positioning themselves as a step up from traditional fast food in terms of quality, for a little extra money. They also offer greater customization.

Globally, McDonald’s said sales declined 0.3 percent at locations open at least 13 months in February. It warned its performance so far could hurt first-quarter profits.