This article is originally from this website: www.discover-the-truth.com
We are approaching the time of the year, where Christians around the World celebrate the supposed birth of Jesus Christ (peace be upon him), which is December 25th. Question arises:- ‘is there any evidence from the Bible for the assumed date, 25th December?’ The Gospel of Luke relates the time, the birth of Jesus Christ:
Luke 2:8 “And there were shepherds living out in the fields nearby, keeping watch over their flocks at night.9 An angel of the Lord appeared to them, and the glory of the Lord shone around them, and they were terrified. 10 But the angel said to them, “Do not be afraid. I bring you good news that will cause great joy for all the people. 11 Today in the town of David a Savior has been born to you; he is the Messiah,the Lord. 12 This will be a sign to you: You will find a baby wrapped in cloths and lying in a manger.”
Notice, the shepherds were abiding out-door in the field. They had their flocks in the field at night. The imagery of the shepherds living out in the fields’, in the open field at night, and it is the coldest part of the day, and the coldest season of the year is absurd for some Christians to say that ‘Jesus was born in December’. No shepherd would be outside at that time of the year, sitting outside in the field watching their flocks. Common wisdom suggests that Jesus Christ was born in spring and possibly summer time the latest, but not winter time. The evidence presented from the Gospel of Luke thus shows that Jesus could not have been born in December.
C. L. Chapman in his book ‘Rightly Dividing the Word of Truth’ writes:
“The Idea of shepherds being in the field in the middle of winter is outrageous. The birth of Jesus had to be in the spring, summer or, most probably, the fall.”
Holman Christian Standard Bible ‘Harmony of the Gospels’ also comments:
“The closest thing to biblical evidence is the reference to the shepherds watching over their flocks at night in the open fields (Lk 2:8). This would indicate a night-time birth (hence our Christmas Eve traditions). It would also seem to indicate a birth between March and November, since the sheep were usually kept in folds rather than in pen fields during the winter months, making our December date of the observance suspect.”
It is commonly known among Christian clergy that 25th December was chosen by the Church to adopt and absorb pagan festivals. So whose Birthday are Christians really celebrating on the 25th December? The answer, they are celebrating the pagan god Mithras. The Persian god Mithras’s birthday had always been celebrated on 25th December.
Episcopal Deacon Vicki K. Black says:
“….Christians in the fourth century decided to adopt December 25 as their feast of Jesus birth. This was the day that the Romans celebrated the birthday of the ‘unconquerable sun,’ a festival in honor of the sun-god Mithra, a deity of Persian origin. The festival was linked to the winter solstice and was a day marked by joyful celebration and great splendour in Rome, making it a fitting date for Christians to celebrate the birth of their own ‘unconquerable Son.’ So from the very beginning Christians has shared it day with celebrations from other religions.” 
Reverend Scotty McLennan also admits that the birthday of the god Mithra was celebrated on the 25th December:
“In the ancient Roman world, December 25 was celebrated as the birthday of the god Mithra, who was identified with the sun and called the sun of righteousness. Along with his December 25 birthday date, the title ‘sun of Righteousness’ was subsequently transferred from Mithra to Jesus and is preserved that way in the third verse of the Christmas carol ‘Hark the Herald Angels sing.’” 
In the book ‘An Introduction to the Bible’ written By Robert Kugler and Patrick J. Hartin say that ‘December 25 the was taken over by Christians to celebrate the birth of God’s son’, in reality as they will explain, it was copied from the pagans:
“The mysteries of Mithras originated in Persia, and the cult was very popular among Roman soldiers. In the 3rd Century C.E. it became the state religion of Rome. Women were excluded from participation. Information about this cult is gleaned from carvings found in caves (called Mithraeum) where rituals took place. Mithras was worshipped as the sun-god, who was born on December 25 (the winter solstice) and was visited by shepherds. Later sacrificed a bull (the Zodiac sign of Taurus), and from this bull’s blood came new life. Initiates had to go through seven stages of initiation, each under the protection of a planetary god. These seven stages were a preparation for the eventual salvation that the initiate would experience at death when the soul moved through seven planetary stages to the place from which it originated. Every Mithraeum had a central statue of Mithras slaying a bull. One can note many similarities with the rituals of Christianity: December 25 was taken over by Christians to celebrate the birth of God’s Son on earth, while baptism and common meals were two features that Mithraism and Christianity held in common.” 
Since it is established clearly that Jesus was not born in December, but most probably in Spring or summer time, why do Christians still continue to celebrate Jesus Christ’s birthday on December 25th?
 Rightly Dividing the Word of Truth [Copyright 2010] By C. L. Chapman page 102
HCSB-[Holman Christian Standard Bible] Harmony of the Gospels [Copyright 2007] By Steven L. Cox, Kendell H. Easley page 290
 Welcome to the Church Year: An Introduction to the Seasons of the Episcopal Church [Copyright 2004] By Vicki K. Black page 28
 Jesus Was a Liberal- Reclaiming Christianity for All [Copyright 2009] By Reverend Scotty McLennan page 201
 An Introduction to the Bible [Copyright 2009] By Robert Kugler, Patrick J. Hartin page 345