CHICAGO – It may not be sweater weather yet, but the annual deluge of pumpkin-flavored treats is on its way.

Pumpkin spice lattes will go on sale at McDonald's Corp. restaurants in some regions starting Monday and at Starbucks Corp. cafes the following day. Seattle-based Starbucks said customers can get the drink early this year by whispering a code — "First PSL" — to a cafe barista.

Americans' craving for pumpkin delicacies has become a seasonal ritual that's only grown in recent years. The success of the Starbucks lattes, which the chain started selling about a decade ago, has prompted a deluge of pumpkin-flavored fare, including Pinnacle brand pumpkin-pie vodka from Beam Suntory Inc. and pumpkin-spice Jell-O from Kraft Foods Group Inc.

"Pumpkin itself is a comfort food," said Bill Chidley, brand consultant at ChangeUp in Dayton, Ohio. "It's just a perennial favorite, like turkey at Thanksgiving, eggnog at Christmas, fireworks on Fourth of July."

U.S. pumpkin-flavored sales jumped 14 percent to about $308 million in 2013, according to Nielsen. The extra demand helped push pumpkin prices up 11 percent last year, according to a USDA report from March.

New and seasonal food offerings have become a main strategy that Starbucks and other restaurants are employing to boost sales. McDonald's began selling its pumpkin lattes last year, while Dunkin' Donuts has added pumpkin flavors to muffins, doughnuts and coffees.