Ghosts, goblins, witches & mutants. Candy, chocolate, parties and trick-or-treaters. Might not make sense, but there is astronomy at the origin of Halloween.
Halloween is a crossquarter day. It marks the midpoint between the autumnal equinox in September and the winter solstice in December. While we say winter ‘officially’ begins on December 21st (2010), our attitudes, practices and thoughts, and even the weather, start to point to winter long before the middle of December. It is now, the halfway point between the two traditional season-starting dates, that we feel winter in the air and prepare for the cold, snowy days ahead.
This crossquarter day marked the end of the year in the old Celtic tradition. And is was at the end of the year when the spirits of the dead could more easily interact with the living. Many Halloween traditions originated as ways of warding off evil spirits, not worshipping them or inviting them in.
Halloween being on a Sunday in 2010, many communities invite trick-or-treaters to make their rounds on Saturday night, and some homes will find costumed crusaders knocking on their door both nights in a effort to secure a more full sack of goodies.
By the way, the actual midpoint between the autumnal equinox and the winter solstice isn’t until November 5th.