Since Elizabeth (John's mother) was in her sixth month of pregnancy when Jesus was conceived (Luke 1:24-36), we can determine the approximate time of year Jesus was born if we know when John was born. John's father, Zacharias, was a priest serving in the Jerusalem temple during the course of Abijah (Luke 1:5). Historical calculations indicate this course of service corresponded to June 13-19 in that year (The Companion Bible, 1974, Appendix 179, p. 200).

It was during this time of temple service that Zacharias learned that he and his wife, Elizabeth, would have a child (Luke 1:8-13 [8] And it came to pass, that while he executed the priest's office before God in the order of his course,
[9] According to the custom of the priest's office, his lot was to burn incense when he went into the temple of the Lord.
[10] And the whole multitude of the people were praying without at the time of incense.
[11] And there appeared unto him an angel of the Lord standing on the right side of the altar of incense.
[12] And when Zacharias saw him, he was troubled, and fear fell upon him.
[13] But the angel said unto him, Fear not, Zacharias: for thy prayer is heard; and thy wife Elisabeth shall bear thee a son, and thou shalt call his name John.

See All...). After he completed his service and traveled home, Elizabeth conceived (verses 23-24). Assuming John's conception took place near the end of June, adding nine months brings us to the end of March as the most likely time for John's birth. Adding another six months (the difference in ages between John and Jesus) brings us to the end of September as the likely time of Jesus' birth...........anyway, MERRY CHRISTMAS!