Is Jesus' birthday actually in December during Christmas? Here is the explination why some believe Jesus' birthday is in September. Luke gives the timeline for Jesus' birth. Luke 1:5-27. Zacharias was of the priestly order of Abijah and it was his turn to go into the holy of holies. 1 Chronicles 24:10 lists the divisions of priest with Abijah as the eighth. The priestly rotation begins on the first of Nissan which is the first month of the Jewish sacred year which falls in March or April. Zarachias would have gone into the holy of holies on the 8th week after Nissan. Luke 1:24. Therefore Zarachias and Elizabeth conceived John the Baptist in May or June. Luke 1:26 and 36. Mary conceived Jesus 6 months after Elizabeth conceives John the Baptist which would be in November or December. Nine months of pregnancy would be August or September. Revelation 12:1-5 also describes Jesus' birth. "A women clothed in sun" is the constellation of virgo with the moon under her and above her is twelve stars which is the constellation of Leo with 3 "wandering stars" (Jupiter, Venus, Mercury). This rare celestial event with this specific combination of constellations appeared on September 11th 3 B.C.