What is the origin of ground hog day?

Groundhog Day is a popular North American tradition observed in the United States and Canada on February 2. It derives from the Pennsylvania Dutch superstition that if a groundhog emerges from its burrow on this day and sees its shadow due to clear weather, it will retreat to its den, and winter will go on for six more weeks; if it does not see its shadow because of cloudiness, spring will arrive early.

While the tradition remains popular in the 21st century, studies have found no consistent association between a groundhog seeing its shadow and the subsequent arrival time of spring-like weather.^[2]

The weather lore was brought from German-speaking areas where the badger is the forecasting animal. This appears to be an enhanced version of the lore that clear weather on the Christian festival of Candlemas forebodes a prolonged winter.

The Groundhog Day ceremony held at Punxsutawney in western Pennsylvania, centering on a semi-mythical groundhog named Punxsutawney Phil, has become the most frequently attended ceremony.  Other cities in the United States and Canada also have adopted the event

At any rate, Groundhog Day serves as a convenient and whimsical milestone to mark the end of the darkest three months of the year, November, December, and January in the Northern Hemisphere. And whether or not Phil sees his shadow, the will be more hours of daylight from this point on.