What is Jesus's birthday?

Answer 1

No one knows for sure. The New Testament provides conflicting time frames.

Jesus was born on or before 4BCE, because Herod died 4BCE.

Jesus was born on or after 6CE, because Cyrenius became governor of Syria on 6CE:-

Luke2:2 And this taxing was first made when Cyrenius was governor of Syria. 2:3 And all went to be taxed, every one into his own city. 2:4 And Joseph also went up from Galilee, out of the city of Nazareth, into Judaea, unto the city of David, which is called Bethlehem; (because he was of the house and lineage of David:) 2:5 To be taxed with Mary his espoused wife, being great with child.

However, we do know it was on the Feast of Tabernacles (September-October).