Samhain, pronounced “sow-in” (“ow” like in cow), is a Gaelic festival that marks the end of the harvest season and the beginning of winter or the “darker half” of the year. It is traditionally recognized on November 1 and considered the 'Celtic New Year'.

I have a song called just that ....

On 'Later... with Jools Holland' from his 2005 'Magic Time' album Van Morrison plays guitar and sings "In the Celtic New Year" >