What follows is from OneLook's word of the day (most requested on the site today):

Samhain is the winter season of the ancient Celts. The Celts divided the year into four quarters: Samhain (winter), Imbolc (spring), Beltane (summer), and Lughnasadh (autumn). The Celtic year began in November, with Samhain.

Interesting to think about the beginning of the year being a fallow, cold time--a darker time of year. Kind of like the embryo or fetus in darkness.