The modern Groundhog Day celebration, which is centered in Pennsylvania on Punxsutawney Phil, has its roots in a variety of cultural customs that signified the importance of the early days of February, which fall approximately midway between the winter solstice and spring equinox. According to Celtic tradition, for instance, this occasion was observed as Imbolc, a festivity held in honor of the goddess Brigid and the approaching return of the revitalizing forces of spring. The more direct association between the emergence of animals from their dens at this time and the prognostication of weather, however, is generally believed to have developed in Europe sometime in the Middle Ages and was brought to North America by German immigrants, many of which settled in Pennsylvania during the late nineteenth century.