is a faith, largely based upon oral tradition, there isn't any way to correctly trace the time, or season of Jesus' birth. Hell, they can't even find any proof of the Augustinius Caesarian tax forms, as of yet. Future archaeologists might someday find some of the tax stamps, but as yet, they remain in a foggy limbo. Somehow, Joseph and Mary found a reason to travel all the way to Bethlehem of Judea, from Nazareth to register themselves onto the Roman tax rolls, according to the Apostle Luke's texts, that some have said were spoken of by the Virgin Mary. Believe it or discard it as you wish. It's all up to you.