Allehelgensaften refers to the evening before All Saints’ Day, celebrated in Denmark and some other Nordic countries. It is traditionally observed on October 31st, with All Saints’ Day falling on the first Sunday in November in Danish practice. The day has both religious significance and folk traditions, including the idea from folklore that witches and spirits are abroad on this night, in contrast to the solemn remembrance of the deceased on All Saints’ Day. In everyday Danish usage, many people also associate Halloween with this date, though Halloween has different origins and is celebrated as a festive, secular event in many places. Key points:

• Date: Allehelgensaften is the evening before All Saints’ Day, commonly October 31st; All Saints’ Day (Allehelgensdag) is observed on the first Sunday in November in Denmark.
• Meaning: A Christian remembrance of the deceased on All Saints’ Day; Allehelgensaften has folkloric associations with spirits and witches, and is also linked culturally with Halloween in recent decades.
• Observance: Church services and readings for All Saints’ Day; in folk tradition, October 31st is a night of heightened folklore activity; many people associate Halloween customs (trick-or-treating, costumes) with this date, though practices vary by region and year.

If you’d like, I can tailor this into a short Danish-language explanation or provide a side-by-side date comparison for the Danish and English terms.