Apparenetly there is too much dichotomy in the church , we've got official records from Roman Empire saying in March (basically) and the vatican taking the official view of spring "sometime" and die hard fundies saying the DEC 25th (because they have no idea about their own religion of course ). Other's still postulating because of the very few writings about it , that it could have been almost any date. Although if you look up chronological biblical stories it appears to be "spring sometime".

(apologize for my earlier assumption that it was "set in stone" technically speaking that would only be the archeological evidence for someone named Jesus not necessarily "The Jesus" etc).