21st December - Winter solstice

Today the sun will appear to have reached its southerly most point in the heaven; the shortest day/longest night - Winter Solstice
December 22, at 04:48 UTC.   or local Orillia/Toronto: 21. Dec    23:49 EST..

Winter solstice and Christmas
"There is nothing in the Christian Bible to specify the day of Christmas. Prior to the
fourth century, Christ’s birth had been associated with Three King’s Day on January 6.
But the pagans and the newly converted were being a major problem to the church because
they were still celebrating the Unconquered Sun. Nothing the church did or said made a
difference; the winter solstice was just too important a festival.

What the Christians did in this dilemma, was execute a move seen over and over in
history. If you can’t defeat them, and refuse to join them, at least make it appear
that you defeated them. Sometime between AD 354 and 360 a few decades after Emperor
Constantine’s conversion to Christianity, the celebration of Christmas was shifted to
the day of the Unconquered Sun. But the tradition of the Sun god lived on a long time."

And note that St Nikolaus is believed to have died in 343CE/AD. His legend was on the rise.

Or
How the Winter Solstice was stolen by Christmas - an American point of view

Or
Why is Christmas Day on December 25th?

And then one has meteorologists wanting winter to begin December 1st. The thermal inertia of the earth means that climate follows the sun, does not preceed it. So January 1st would be a practical beginning of winter
and then spring April 1 - we have been fooled by spring often enough - why not once more! And summer July1st and autumn October 1 - if the weathermen cannot start on the astronomical date, then at least on the psychological one, please.

And to finish the successful return of the sun let us not forget New Year's eve and Janus the two-headed Roman god who looks both backward and forward, a fitting end to 2015 and start to 2016