Confused 2nd timer - does heat break down THC?

Hi there, have a question (coming from a legal municipality):

Recently picked up a 1g preroll of cannabis from the dispensary and left it in my car for a week (ambient temps around 41°). When I went to smoke it, it smelled the same and looked the same (was in a sealed plastic container) but it had no effect whatsoever. Does THC degrade at high ambient temps?