Jesus was not born in the winter season! When the Christ-child was born "there were in the same country shepherds abiding in the fields, keeping watch over their flock by night" (Luke 2:8). This could never have occurred in Judea in the month of December. The shepherds always brought their flocks from the mountainsides and fields and corralled them not later than October 15, to protect them from the cold, rainy season that followed that date. Notice that the Bible itself proves, in Song of Solomon 2:11 and Ezra 10:9, 13, that winter was a rainy season not permitting shepherds to abide in open fields at night.
"It was ancient custom among Jews of those days to send out their sheep to the fields and deserts about the Passover (early spring), and bring them home at commencement of the first rain," says the Adam Clarke Commentary (vol. 5, p. 370, New York ed.).
Continuing, this authority states: "During the time they were out, the shepherds watched them night and day. As . . . the first rain began early in the month of Marchesvan, which answers to part of our October and November [begins sometime in October], we find that the sheep were kept out in the open country during the whole summer. And, as these shepherds had not yet brought home their flocks, it is a presumptive argument that October had not yet commenced, and that, consequently, our Lord was not born on the 25th of December, when no flocks were out in the fields; nor could He have been born later than September, as the flocks were still in the fields by night. On this very ground, the nativity in December should be given up. The feeding of the flocks by night in the fields is a chronological fact."
Any encyclopedia, or any other authority, will tell you that Christ was not born on December 25. The Catholic Encyclopedia frankly states this fact.
The exact date of Jesus' birth is entirely unknown, as all authorities acknowledge—though there are indications that it was in the early fall—probably September—approximately six months after Passover.