Groundhog Day, celebrated across the United States and Canada, on February 2, is purely a North American tradition. It is based on a belief that on this day (February 2) the groundhog, or woodchuck, comes out of hole after winter hibernation to look for its shadow. If the shadow is seen, it's a sunny day. And the groundhog foretells 'six more weeks of bad weather' and thus a lingering winter. But spring is coming if no shadow is seen because of clouds. The groundhog then behaves accordingly. It goes back into the hole if the weather turns bad, but stays above ground if spring is near.

Thus weather prediction or prognostication came as an integral feature of Groundhog Day tradition. This prediction owes its origin to the European tradition of Candlemas. There is an old European supposition that a sunny Candlemas day would lead the winter to last for 'another six weeks'. Also celebrated on February 2, the was used to commemorate the Purification of the Virgin Mary. Candles for sacred uses were blessed on this day. Gradually the traditions at this Candlemas came to associate with them different folklores. The German added the belief of an animal, initially a hedgehog, being frightened by his shadow on Candlemas would foretell that winter would last another six weeks. This belief was brought in America during the 18th Century by the German settlers. These settlers adopted the groundhog as their weather predictor.

The Groundhog Day came into being in North America during the late 1800s. Thanks to the combined effort of Clymer H. Freas, a newspaper editor, and W. Smith, an American Congressman and newspaper publisher. They organized and popularized a yearly festival in Punxsutawney, Pennsylvania, the State was populated predominantly by German settlers. The festival featured a groundhog named Punxsutawney Phil which used to foretell how long the winter would last. This very popular event is still being held and is called Groundhog Day.

There has been a concerted effort in popularizing and commercializing the Groundhog Day across the United States. Chuck Wood is The Committee for the commercialization of Groundhog Day's official mascot. The movie "Groundhog Day," has played a key role in popularizing the schedule of Events in Punxsutawney, Pennsylvania, on and around February 2. Apart from Pennsylvania, fascinating Groundhog Day events are also held in other states, especially, Nebraska, Tennessee, Georgia, Ohio, Arkansas, and California.

The Groundhog Day is also very popular in Canada and Wiarton Willy is the Groundhog that is used to predict the length of winter over there.