Score Free Coffee at California Dunkin' Stores This Summer.

Dunkin' is offering a free medium coffee with any purchase every Monday through June 26 to California residents who sign up for the rewards program and use the Dunkin' app. The chain is also offering single-use deals to rewards members who sign up before the end of May, including a $2 medium signature latte, free medium iced coffee, free medium Dunkin' refresher, and a $2 ham and swiss croissant. Specific purchases may be required to unlock these deals and some exclusions may apply.