Biblical scholars and historians are unsure of the actual date of the birth of Jesus Christ. Most experts believe that the Catholic Church chose December 25 to celebrate the birth of Christ because it fell around the same time as Saturnalia, a Roman Festival.
In the early days of the Christian Church, little emphasis was placed on celebrating the birth of Christ, and very little information of his birth exists in the gospels. Because December is a cold month in Bethlehem where Jesus was born, some scholars argue that Jesus' birth took place in a warmer month, most likely September. With a September birth, some of the accompanying stories, such as Mary and Joseph traveling and the shepherds working in the fields, are much more plausible.