Groundhog Day is pretty much just a day for TV to get some cheap coverage of a non-event in. Nobody has much faith in the groundhog, or really in the ability of a cold clear sunny day, versus a warmer cloudy day, to predict the weather beyond tomorrow.
But Groundhog Day marks one of the old Druid cross-quarter days, which the Christians (and others) tried to stamp out by putting other stuff on top of it.
The cross-quarter days are halfway in between the bigger days of equinox (spring and fall, when the day is of the same length as the night) and solstice (when the day is at its longest in the summer or shortest in the winter). Of course, Christmas came to be celebrated near the winter solstice.
February 2 is Candlemas Day in the Catholic calendar, when candles were blessed – better to light a candle than curse the darkness. The day after is the feast of St. Blaise, when throats were blessed with those blessed candles.
Another cross-quarter day is November 1, which became the Feast of All Saints, followed by November 2, All Souls Day – and preceded by Halloween, which preserves some of the spooky fear of the dark in cartoonish form.
May 1 became May Day in the labor movement, and the somewhat unsuccessful Feast of St. Joseph the Worker as a countermeasure.
August 1 didn’t really become much of anything, just as the summer solstice doesn’t seem to have been nearly as big a deal as the winter solstice. Just too many distractions in the summer, even in ancient times.
The dates are now pretty approximate due to the movement in days up to the Gregorian stabilization of the calendar. February 6 would be closer to halfway between the winter solstice and the sprint equinox now. But then the Druids aren’t what they used to be, either.
The cross-quarter days are the four traditional Celtic festivals celebrated by Neopagans. Along with the Quarter Days, they make up the "Wheel of the Year." These holidays "cross" the quarter days (the solstices and the equinoxes) by falling about halfway in between, thus dividing the year into four parts of approximately three months each. They are also known as Imbolc (February 1), Beltane (May 1), Lammas (August 1), and Samhain (November 1). These Gregorian calendar dates are less than exact, however; February 6, May 6, August 6, and November 6 actually fall closer to the halfway point between the equinoxes and solstices.
Read more: http://www.answers.com/topic/cross-quarter-day#ixzz2JmXPsqrL