There is no certain date, just a certain day. Don't know how they work it out other then that, don't think it matters. Christmas was the pagan winter solstice, hence why J.W's draw the hard line and don't celebrate it at all. But us Prodestants celebrate it because it's not a pagan holliday to us, and that's what makes the difference. I celebrate it all the more because it shows that God can turn something that celebrated evil, into something that celebrated good. Much like what He has done to all those people who were in darkness but now have seen the light, sorry about sounding dramatic, but I think it's pretty cool.
CyA's
CyA's