Would you believe the tradition of Groundhog Day comes from Europe? The idea originates from Christianity or, rather, Candlemas Day. On this day, the clergy were to bless and distribute candles that were necessary for survival during a long, cold winter. These candles were also symbolic for the length and weather conditions of winter.
Germans added to this idea by designating an animal as the official means by which the weather was predicted. They had a hedgehog come out and if it saw it's shadow, then you could expect six more weeks of winter. If it didn't, then you could expect an early spring. When the Germans came to America and settled in Pennsylvania, they brought this tradition with them. There were, however, no hedgehogs in Pennsylvania but many, many groundhogs. The groundhog then became the official prognosticator of the winter season.