The Bible’s answer
The Bible does not give a specific date for the birth of Jesus Christ, as these reference works show:
“The true birth date of Christ is unknown.”—New Catholic Encyclopedia.
“The exact date of Christ’s birth is not known.”—Encyclopedia of Early Christianity.
While the Bible does not directly answer the question, ‘When was Jesus born?’ it does describe two events surrounding his birth that lead many to conclude that he was not born on December 25.
Not in winter
The registration. Shortly before Jesus was born, Caesar Augustus issued a decree ordering “all the inhabited earth to be registered.” Everyone had to register in “his own city,” which might have required a journey of a week or more. (Luke 2:1-3) That order—probably made to support taxation and military conscription—would have been unpopular at any time of year, but it is unlikely that Augustus would have provoked his subjects further by forcing many of them to make long trips during the cold winter.
The sheep. Shepherds were “living out of doors and keeping watches in the night over their flocks.” (Luke 2:8) The book Daily Life in the Time of Jesus notes that flocks lived in the open air from “the week before the Passover [late March]” through mid-November. It then adds: “They passed the winter under cover; and from this alone it may be seen that the traditional date for Christmas, in the winter, is unlikely to be right, since the Gospel says that the shepherds were in the fields.”
In early fall
We can estimate when Jesus was born by counting backward from his death on Passover, Nisan 14 in the spring of the year 33 C.E. (John 19:14-16) Jesus was about 30 years old when he began his three-and-a-half-year ministry, so he was born in the early fall of 2 B.C.E.—Luke 3:23.
Why is Christmas on December 25?
Since there is no evidence that the birth of Jesus Christ occurred on December 25, why is Christmas celebrated on this date? The Encyclopædia Britannica says that church leaders probably chose it “to coincide with the pagan Roman festival marking the ‘birthday of the unconquered sun,’” at the time of the winter solstice. According to The Encyclopedia Americana, many scholars believe that this was done “in order to make Christianity more meaningful to pagan converts.”