There is not a lot of information in the Bible about when Jesus was born. There are some clues, however, ambiguous though they are. In Luke 2:8, it talks about how the shepherds are tending to their flocks when the news of His birth comes. This suggests a spring date, rather than the traditional one of December 25, because in December, one would think that the sheep would be corralled for the winter.
Initially, there were two possible dates for the birth of Jesus, both arrived at a long time after His death. One was December 25; the other one was January 6. The Armenians kept to the latter date, but the West established the former. In the West, January 6, twelve days after Christmas, became the Feast of the Epiphany. The selection of December 25 to represent the date of Jesus’s birth had a purpose behind it; it was to spread the gospel throughout the entirety of Roman civilization, because that is when they celebrated their pagan holiday.
I know that Shakespeare’s “Twelfth Night” celebrates the Saturnalia, ending in the twelfth night after Christmas, and that this is a Roman holiday, a pagan tradition.
According to the Roman calendar, Jesus’s crucifixion occurred on March 25. Nine months. I do not know if there is a connection between this and the fact that nine months is the normal gestation period for a human baby. My own thought is that perhaps when we die, we enter into a kind of probationary period for nine months as we just adjust to our new world.
However, the usage of calculating when exactly Jesus was born, based on the 9 month period, also causes another date to be possible. In the East, the date for Christmas was January 6, remember, and nine months from that date is April 6.
Regardless of exactly when Jesus was born, His message is still the same. Love each other, try to do what is right. He atoned for us so that we can return to live with our Heavenly Father. That is the greatest Christmas gift of all.