Groundhog Day. As early as 1886, German immigrants here observed Groundhog Day and established the Punxsutawney Groundhog Club in 1899. According to folklore, if the hibernating groundhog - known as Punxsutawney Phil - leaves its burrow on February 2 and sees its shadow, there will be six more weeks of winter. The legend is based on a European custom predicting the length of winter by weather conditions on Candlemas, an ancient Christian festival.