Groundhog Day is celebrated in the States on 2 February, when the said beast emerges from winter hibernation. If he sees his shadow, this foretells the imminent end of winter. If he sees his shadow due to the wether being bright, he runs back underground and winter will continue for 6 more weeks.
But the date coincides with the ancient Christian celebration of Candlemas, which celebrates the ritual purification of Mary 40 days after giving birth to Christ, and the presentation of the child to the Temple of Jerusalem, but according to Jeremy Hobson in Curious Country Customs, it is yet another Christian adaptation – or hijacking- of a pagan custom celebrating the halfway point of winter, as it is half way between the winter solstice and the spring equinox.
There is a saying ‘A farmer should, on Candlemas Day, have half his corn and half his hay.’
So, for our agrarian ancestors, this was an important date for their consumption of the year’s food. In churches, it was when candles for altars and general lighting were blessed and smaller candles taken home by parishioners to protect their homes from evil. In pre-Christian times, it was celebrated as the festival of light.