Scripture shows when John was conceived, and Jesus was conceived six months later.
Luke 1:5 ¶There was in the days of Herod, the king of Judaea, a certain priest named Zacharias, of the course of Abia: and his wife was of the daughters of Aaron, and her name was Elisabeth.--
The courses began with the first month, Abib.=March-April--The course of Abia fell around our late May to early June.
Luke 1:23 And it came to pass, that, as soon as the days of his ministration were accomplished, he departed to his own house.
24 And after those days his wife Elisabeth conceived, and hid herself five months---
Luke 1:26 ¶And in the sixth month the angel Gabriel was sent from God unto a city of Galilee, named Nazareth,---early December.
27 To a virgin espoused to a man whose name was Joseph, of the house of David; and the virgin's name was Mary.
30 And the angel said unto her, Fear not, Mary: for thou hast found favour with God.
31 And, behold, thou shalt conceive in thy womb, and bring forth a son, and shalt call his name JESUS.
36 And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren.
37 For with God nothing shall be impossible.
This would put the dates as follows.--Roman Calendar vary's from Jewish.
3rd month.-Sivan/ May-June/ Conception of John
1st. month.-Abib / March-April / Birth of John
9th. month- Chisleu / Chislev / Kislev/ November-December / Conception of Jesus
7th month- Ethanim / Tishri /September-October / Birth of Jesus
The courses- see-- 1 Chron.24: 7-18
John would have been conceived in early June
Christ would be 6 months later in early December.
All priests worked the weeks with Holy days.
1st Month Abib - Nisan-(March - April)
2nd Month-Zif - Iyyar-(April - May)
3rd Month - Sivan- (May-June)
Christ's birth would not have taken place in winter.
Large crowds of people would not care to be baptized in winter.
Luke 3:21 ¶Now when all the people were baptized, it came to pass, that Jesus also being baptized, and praying, the heaven was opened,
22 And the Holy Ghost descended in a bodily shape like a dove upon him, and a voice came from heaven, which said, Thou art my beloved Son; in thee I am well pleased.
23 And Jesus himself began to be about thirty years of age, ---The age when prophets began to serve.
Christ became Our Passover around March, when He was 33 1/2 years of age.
The Emperor of Rome re-named Saturnalia, the pagan Roman festival, a "Mass for Christ" to make the pagan holiday appear Christian.