Australia is exceptionally bad for the sun. It's crazy because the incidence of skin cancer is still so high even though sun protection is drilled into us since birth. I'll rant further that Australia is not even good from a UV/temperature tradeoff because the UV is always ridiculously high. Nice warm Mediterranean summer UV level is equivalent to a freezing cold winter day in Australia.
It's because you're the same latitude as Namibia, Botswana etc. Even Perth is on the same equivalent (south instead of north) as Cairo or Kuwait.
There's a reason the indigenous Australians stayed dark skinned after 40,000 years - a time frame more than long enough for the Irish to turn red-haired and pale; as a trait it's relatively fast evolving, Europe probably evolved most/all of its variation since the last ice age.
