On Saturday, the custom of Groundhog Day was celebrated. The most well-known celebration and prediction, which occurs in Punxsutawney, PA and features Punxsutawney Phil, claimed that an early spring is coming because the groundhog did not see his shadow. If he had seen his shadow, the prediction would have been for six more weeks of winter.
The predictions of Punxsutawney Phil have been correct only 39% of the time dating back to 1887, according to the StormFax Weather Almanac. Such a record is unsurprising, as the future is unknown and unknowable. Notably, he almost always sees his shadow; 2013 is only the 17th time out of 117 predictions on record that he has not seen his shadow.
The custom of Groundhog Day was brought to America by Pennsylvania Dutch settlers in the 17th and 18th centuries. The customs used badgers, bears, or hedgehogs for weather divination in Europe, but the settlers switched to groundhogs because hedgehogs do not live in North America, and badgers and bears were uncommon in the settled areas.
The practice of weather divination in general goes back to the Celtic calendar. In the Celtic calendar, the seasonal turning points are marked not by solstices and equinoxes (as in the Gregorian calendar), but by the midpoints in between, known as cross-quarter days. These days are Imbolc (between the winter solstice and spring equinox), Beltaine (between the spring equinox and summer solstice), Lughnasadh (between the summer solstice and autumn equinox), and Samhain (between the autumn equinox and winter solstice). On each of these days, the boundaries between the physical world and the spiritual world were thought to be more easily permeated, leading to weather divination practices on each of the four cross-quarter days. The practices concerning Imbolc (usually celebrated on February 1) are part of the basis for Groundhog Day.