October 31 'Halloween'
AKA Hallowe'en, All Hallows, the last night of summer, Celtic New Years Eve, Nutcracker Night, All Saints Eve. 'All Hallow's Eve' or 'Samhain', the transition from autumn to winter.

Wicca festival of the eve of 'Samhain', translates from the Gaelic as the 'End of the Summer', and the 'Coming of Darkness' / winter.

The Celtic Brigid (1 February) and Columcille (7 June) were joint protectors of cattle and it was the practice at this time to ask for protection during the periods of Samhain, Imbolc to Beltane:

'Everything within my dwelling or in my possession,
All kine and crops, all flocks and corn,
From Hallow Eve to Beltane Eve.'

Celtic feast day of 'Erc', fifth century, Irish missionary. Reputed to have been converted by Patrick (17 March). St Erth, Cornwall, England is believed to have been named in his honour.