Christmas is hot. It's summer. It's just always been normal. Like Peter2, my biggest novelty was the only holiday period I spent somewhere completely different, where snow on New Years Eve in Edinburgh was about the best thing that had ever happened.
In terms of fires, we obviously had that terrible period last December. I was in New Zealand over Christmas & some of the snow on the mountains was pinkish-yellow, due to all the ash that had drifted across the ocean. Then about 2 weeks later is actually hit South America, by all accounts. We have bushfires pretty frequently so December was not particularly exceptional in that sense, although the heat was such that many separate fires pretty much combined into one huge front.
But the difference in Australia is that we are largely empty. Fires need something to burn, and trees (largely) only grow near the coast out here (say within a couple of hundred kms). But that just happens to also be where all the people are: we have roughly 23 million people squeezed - to the surprise of many people, with some of the highest density in the world - largely into a narrow habitable band along the coasts. The interior is largely empty, so the extreme temperatures are pretty much unrecorded, there's nothing to burn in the first place, and nothing to destroy if it did.
Somewhere like the US is completely different because it's full. California alone has almost twice as many people as the entire of Australia. And despite the heat, trees still grow, and many more people live near them, so wildfires are a much bigger threat to life and property. Our fires destroy large areas of forest, probably more than California even now, but in relatively uninhabited areas. It's still a tragedy, of course, but the scale of life and property loss is in the low hundreds - smaller size fires are far bigger human disasters in California.