Before there was Groundhog Day, there was St. Bridget’s Day.
Before there was St. Bridget’s Day, there was Imbolc.
Imbolc in its original form was associated with the Gaelic goddess, Brigid in her role as a fertility goddess and heralds the onset of spring. It was later Christianized as St. Bridget’s Day and sometimes tends to be merged with Candlemas.
Imbolc is variously associated with February 1st, the Full Moon mid-way between the Winter Solstice and the Vernal Equinox, or the first blooming of blackthorn. Customs for observing Imbolc vary among neopagans but usually include symbolic hearthfires or candles representing the return of the Sun. The ritual of “spring cleaning” has also been associated with this holiday.
The modern association with Groundhog Day may be related to weather divination practices originally associated with Imbolc. In Gaelic tradition, foul weather on Imbolc was a sign that winter would soon be over.