xkcd #3202: Groundhog Day Meaning
Title text:
Originally, the ceremony used a variety of rodents and mustelids, but over time most people agreed it made sense to standardize on a specific individual ground squirrel in Pennsylvania.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3202/
I mean, it doesn't have anything to do with the movie Groundhog Day in which the main character relives Groundhog Day over and over again? I don't think anybody used "groundhog day" as a synonym for "personal time loop" before the movie.
Why do you think they named the movie and holiday "Groundhog Day"? From the rodents waking up from a months long coma? That'd be silly. It has always been about time loop.