According to Luke 1:24-26, Mary conceived Jesus in the sixth month of Elizabeth's pregnancy with John the Baptist. This means that Jesus was born 15 months after the angel Gabriel appeared to Elizabeth's husband, Zacharias, and informed him that his wife would bear a child.
According to Luke 1:5, Zacharias was a priest of the division of Abijah. Luke 1:8 says that Gabriel appeared to Zacharias while he was serving as a priest in the Temple.
We know from the Talmud and other sources that the division of Abijah served as priests during the second half of the fourth month of the Jewish religious calendar — which would have put it in late June (the Jewish religious calendar begins in March with Passover).
Fifteen months later would place the birth of Jesus in the seventh month of the Jewish calendar. That would be in the fall of the year, in either late September or early October. His conception, not His birth, would have occurred in December of the previous year.
The seventh month of the Jewish calendar is the month of the Feast of Tabernacles. John 1:14, speaking of Jesus as the Word, says: "And the Word became flesh and dwelt among us, full of grace and truth." The word "dwelt" that is used here is the Greek word "skenoo" which literally means "to tabernacle"!
So, when God came to earth to tabernacle among Men it appears that He timed His arrival in the Bethlehem manger to coincide with the Feast of Tabernacles. That was only appropriate, for the Feast of Tabernacles is the most joyous of all the Jewish feasts. It is, in fact, their feast of thanksgiving.
The total meaning of that feast will not be fulfilled until the Lord returns again to tabernacle among Men for a thousand years while He reigns over the earth from Mt. Zion in Jerusalem. Isn't the Word of God marvelous?