Let's start with explaining what is what...
Best time of the year, Christmas:
Christmas is an annual festival commemorating the birth of Jesus Christ, celebrated primarily on December 25 by billions of people worldwide as a religious and cultural celebration. It is a central feast in the Christian liturgical year, preceded by the season of Advent or the Nativity Fast, and begins the season of Christmastide, which traditionally lasts twelve days and culminates on Twelfth Night. Christmas Day is a public holiday in many countries, is religiously observed by the majority of Christians and culturally observed by many non-Christians, and is an important part of the holiday season.
According to the traditional Christmas tale told in the New Testament, known as the Nativity of Jesus, Jesus was born in Bethlehem in accordance with messianic prophecies. When Joseph and Mary arrived in town, the inn was full, so they were offered a stable, where the Christ Child was soon born, with angels announcing the news to shepherds, who then spread the word.
"Then what is Yule?" you may ask:
Yule is an event celebrated historically by the Germanic peoples. Scholars have linked Yule's origins to the Wild Hunt, the god Odin, and the pagan Anglo-Saxon Mdraniht ("Mothers' Night"). Some modern Christmas customs and traditions, such as the Yule log, Yule goat, Yule boar, Yule singing, and others, may have pagan origins. Yule and cognates are still used to designate Christmas and other winter holiday festivities in English, Nordic languages, as well as Finnish and Estonian.
If you wonder, and you surely do, the differences between Yule and Christmas are:
Originally, they were completely different things.
Yule was a winter Germanic festival. For a time, pagan holiday Yule and Christmas were celebrated, which resulted in some cultural exchanges as Christianity was fully adopted. Even though Christmas is a different celebration, the name Jul/Yule was commonly used in Nordic countries to refer to it. Finally, Christmas contains very few elements that are actually from pagan Yule, and most of that people say are pagan in origin, such as Christmas trees, only appear in later medieval and early modern times.
-Ardko (as he explained further and deeper in this following video)