Whitmere was born on May 8, 1981 in Timmins, Ontario. She spent her first years in the Arctic community of Kuujjuarapik, Quebec.
Whitmere appeared in her first play as a child, and spent her high school years training at Walnut Hill School, a performing arts boarding school in Natick, Massachusetts. After working in Montreal for some years, Wetmore moved her base of operations to Toronto in 2004. She now divides her time between Toronto and Los Angeles.
On August 20, 2005 she married Terry McGurrin, the star of Comedy Inc., a comedy show Whitmere once wrote for.