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

The weather lore was brought from German-speaking areas where the badger is the forecasting animal. It is related to 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. Grundsow Lodges in Pennsylvania Dutch Country in the south-eastern part of the state observe the occasion as well. Other cities in the United States and Canada also have adopted the event.

In 2024, no shadow so an early spring was predicted.

Punxsutawney Phil's statistics are kept by the Pennsylvania's Groundhog Club which cares for the animal. Phil has predicted 106 forecasts for winter and 19 for an early spring. One year he had a partial shadow, in 1942. There were 10 years where Phil's prediction was not recorded, all of which occurred in the 1880s and 1890s. There has been one year where the event was canceled (1943) due to World War II.

Most assessments of Phil's accuracy have given an accuracy lower than would be expected with random chance. Stormfax Almanac gives Phil an estimate of 39% accuracy.