After completing his service, his wife Elizabeth became pregnant.
Nine months later, John the Baptist was born around March or April.
Six months into that pregnancy, the angel Gabriel visited Mary. This places the conception of Jesus around September.
Nine months later, Jesus would have been born between the end of September and the beginning of October.
The Connection to the Feast of Tabernacles
This period coincides with the Feast of Tabernacles (Sukkot), one of the most important celebrations in the biblical calendar, which commemorates when God dwelt among his people in the desert.
John 1:14 says that “the Word became flesh and dwelt among us.” In the original language, that word literally means “tabernacled.”
That is, Jesus would have been born precisely when Israel was celebrating God dwelling with his people.
Why was there no room at the inn?
In December, Bethlehem was a quiet town.