Why is Halloween always on the 31st?

Halloween is always celebrated on October 31st due to its origins in the ancient Celtic festival of Samhain, which was observed on the same date. Samhain marked the end of the harvest season and the beginning of winter, a time when the Celts believed the boundary between the living and the dead was at its thinnest, allowing spirits to cross into the world of the living.

When Christianity spread across Europe, many pagan traditions were adapted into the Christian calendar. Pope Gregory III designated November 1st as All Saints' Day, also known as All Hallows' Day, to honor saints and martyrs. The evening before, October 31st, became known as All Hallows' Eve, which eventually shortened to "Halloween."

The date of October 31st, therefore, has historical and religious significance, connecting both the Celtic festival of Samhain and the Christian observance of All Hallows' Eve. This is why Halloween is always celebrated on October 31st, regardless of the day of the week it falls on.