Halloween and related celebrations: Samhain in the Northern Hemisphere, Beltane in the Southern Hemisphere; begins on sunset of October 31 (Gaels, Welsh people and Neopagan Wheel of the Year)

Samhain or Sauin is a Gaelic festival on 1 November marking the end of the harvest season and beginning of winter or the "darker half" of the year. It is also the Irish and Scottish Gaelic name for November. Celebrations begin on the evening of 31 October, since the Celtic day began and ended at sunset. This is about halfway between the autumnal equinox and winter solstice. It is one of the four Gaelic seasonal festivals along with Imbolc, Bealtaine, and Lughnasa. Historically it was widely observed throughout Ireland, Scotland, and the Isle of Man. Its Brittonic Celtic equivalent is called Calan Gaeaf in Wales.

Beltane or Bealtaine is the Gaelic May Day festival, marking the beginning of summer. It is traditionally held on 1 May, or about midway between the spring equinox and summer solstice. Historically, it was widely observed in Ireland, Scotland, and the Isle of Man. In Ireland, the name for the festival in both Irish and English is Lá Bealtaine. In Scottish Gaelic it is called Là Bealltainn, and in Manx Gaelic Boaltinn or Boaldyn. It is one of the four main Gaelic seasonal festivals—along with Samhain, Imbolc, and Lughnasadh—and is similar to the Welsh Calan Mai.

The Irish calendar is the Gregorian calendar as it is in use in Ireland, but also incorporating Irish cultural festivals and views of the division of the seasons, presumably inherited from earlier Celtic calendar traditions.

The Welsh are an ethnic group and nation native to Wales who share a common ancestry, history and culture. Wales is one of the four countries of the United Kingdom. The majority of people living in Wales are British citizens.