Christmas was formerly observed in the Highlands on what is now known as “Twelfth Night”. In the Celtic lands, the people did not at first take to the introduction of the New Style calendar in 1752, and tenaciously clung to the ‘old way’ of things, including their conviction of Jan. 6th as the “real” Christmas day. Still celebrated in Ireland as Nollaig na mBan:

https://www.irishcentral.com/roots/womens-christmas-nollaig-na-mban-celebrate-ireland

http://en.wikipedia.org/wiki/Little_Christmas

http://thedailyedge.thejournal.ie/nollaig-na-mban-1251251-Jan2014/

http://bigreaders.myfastforum.org/archive/oiche-nollaig-na-mban__o_t__t_113.html

The Feast of the Epiphany is also called coir-ceim-coilleach, which means ‘the cocks step’; the first noticeable lengthening of the daylight hours.

From Twelfth Day, the day begins to lengthen by a male hen’s span or stride, Breton Proverb.

Meaning a little each day

There is a hint here of how different cultures measure the year and time.

For the Pre Islamic Arab world:

https://en.wikipedia.org/wiki/Islamic_calendar#Pre-Islamic_calendar