The Origins of December 25th as Christmas Day
The birth of Jesus Christ cannot be connected with December 25th unless we consider history. Many do not even understand that the date for Christmas was not the exact date Christ was born. No one knows the real birth date of Jesus!
Even though the birth of Jesus Christ could be some time between 2 to 7 BC, the first celebration of Christmas on December 25th came up in 336 BC, which was during the reign of Emperor Constantine of Rome. However, it was an official Roman festival then and was quite different from the christmas celebrations we have come to know today.
Some side of the myth traced the birth of Jesus 9 months from the date of the celebration of the Annunciation, which is celebrated on March 25th till today.
Some Christians believed that the world was made on March 25th also and also the date Jesus had died in his adulthood (14, Nisan from the Jewish calendar). So, for them, Jesus was born, and he died on that same day.
The Pagan Roots of Christmas Festivities
The ancient festival by the pagans in the midwinter time, ‘Saturnalia’ and ‘Dies Natalis Solis Invicti’ and the Winter Solstice, which took place in December around this date, is also one of the stories as they saw that time as one when there are just general celebrations.
Hannukah, the Jewish festival of lights which starts on the 25th of Kislev (a month in the region of December in the Jewish calendar), can also pass as one of the reasons. Since Jesus was a Jew, the early church could have chosen this time for this purpose.
There are several other stories out there about the roots of Christmas. This is the reason there is no specific explanation for why Christmas is celebrated across the world on December 25th.