"There is no Christian origin to the celebration. It is Pagan in its origins and most Christians know that. Christ was born when the sheep were on high ground being sheared. That wouldn't be dead winter."
It is a commemoration of the Nativity.
Our Lord told us that the Sabbath was made for man, not man for the Sabbath. Reasoning from that principle, if it is more felicitous for us men--for historical and practical reasons--to celebrate Christmas in mid-winter, then I very much doubt that God minds in the least.
I didn't say God minds that we celebrate Christ's birthday on the wrong day and season. Just a factual iota that the celebration is not Christian in its origins.