I honestly cannot speak for everyone, of course we have our own Aussie Christmas carols with your reindeers replaced with kangaroos which to me seem more to be satire. But we have still been Nothern-hemispherized in the traditional christmas sense. Our decorations have snow, every figurine is rugged up etc. I could send you a picture of my christmas tree, it would be indistinguishable from your generic tree.

It surely doesn't snow in all parts of the Northern Hemispher and I guess you can draw similarities to that. The funny thing is, for more Christmas's then I can remember, it has actually been quite wet and stormy, today it is beautiful and sunny.