Groundhog Day is an annual holiday celebrated on February 2nd in the United States and Canada. A groundhog (Marmota monax) is a rodent of the family Sciuridae, belonging to the group of large ground squirrels.
According to folklore, if a groundhog emerging from its burrow on this day fails to see its shadow, it will leave the burrow, signifying that winter will soon end. If on the other hand, the groundhog sees its shadow, the groundhog will supposedly retreat into its burrow, and winter will continue for six more weeks.
The holiday, which began as a Pennsylvania German custom in southeastern and central Pennsylvania in the 18th and 19th centuries, has its origins in ancient European weather folklore, wherein a badger or sacred bearis the prognosticator as opposed to a groundhog.