When German settlers arrived in the 1700s, they brought a tradition known as Candlemas Day, which has an early origin in the pagan celebration of Imbolc. It came at the mid-point between the Winter Solstice and the Spring Equinox. Superstition held that if the weather was fair, the second half of Winter would be stormy and cold. For the early Christians in Europe, it was the custom on Candlemas Day for clergy to bless candles and distribute them to the people in the dark of Winter. A lighted candle was placed in each window of the home. The day's weather continued to be important. If the sun came out February 2, halfway between Winter and Spring, it meant six more weeks of wintry weather.
The earliest American reference to Groundhog Day can be found at the Pennsylvania Dutch Folklore Center at Franklin and Marshall College:
February 4, 1841 - from Morgantown, Berks County (Pennsylvania) storekeeper James Morris' diary..."Last Tuesday, the 2nd, was Candlemas day, the day on which, according to the Germans, the Groundhog peeps out of his winter quarters and if he sees his shadow he pops back for another six weeks nap, but if the day be cloudy he remains out, as the weather is to be moderate."
One of the problems with traditions is that they sometimes do not adapt to changing conditions. It would seem that the European weather on which the tradition was based is not similar enough to North American weather, which is both harsher and more unpredictable due to more of North America being situated far from any oceans along with its location on on the cold side of the Atlantic conveyor current that makes Europe substantially warmer than its latitude would otherwise suggest.
As far as this year goes, in Minnesota we've barely had a winter. There's hardly any snow left and the temperature has been above freezing for at least the last week. But the groundhog saw his shadow as usual. I'm guessing from what I've seen so far that this will be one more year he gets it wrong.