The groundhog wakes up from hibernation on February 2.
If the groundhog sees its shadow when it emerges from its burrow, there will be six more weeks of winter.
If it does not see its shadow, spring will arrive soon.
This tradition started in Europe as Candelmas Day. Germans who settled in Pennsylvania in the 1700s brought the custom to America.
Pennsylvania's Punxsutawney Phil is the most well-known, but more than a dozen states celebrate with their own groundhogs, such as Georgia's General Beauregard Lee and Buckeye Chuck in Ohio.
Punxsutawney Phil - in Punxsutawney, Pennsylvania
His full name is "Punxsutawney Phil, Seer of Seers, Sage of Sages, Prognosticator of Prognosticators, and Weather Prophet Extraordinary.''
February 2, 1886 - The Punxsutawney Spirit newspaper proclaims this date as Pennsylvania's first official Groundhog Day celebration.
Phil has correctly predicted the beginning of spring
100% of the time, according to his owners. However, according to the National Oceanic and Atmospheric Administration, the ground hog shows "no predictive skill" for the last few years.
Phil travels to Washington, D.C. to meet with President Ronald Reagan
Columbia Pictures releases the movie, "Groundhog Day," starring Bill Murray
In the years following the release of the movie, crowds numbering as high as 30,000 have visited Gobbler's Knob in Punxsutawney.
Phil appears on the Oprah Winfrey
January 27, 2010 - The animal rights group PETA suggests using a robotic groundhog in place of Punxsutawney Phil.
February 2, 2010 - For the first time, fans are able to register for a text message alert of Phil's prediction.