Um, don’t compare US winters to winters near Bethlehem—another myth. Israel is on the Mediterranean and closer to Egypt than Greece—so it is highly likely the weather in December was mild—not frigid.

“Winters in North America and Europe are cold and cool whereas summers are hot and or warm … it would be more appropriate to consider seasonality in terms of wet and dry seasons [in Israel]” (“Geography and The Bible (Palestine),” Anchor Bible Dictionary, vol. 2: D-G, p.970).