While it fails to explain the drought, global warming, greenhouse effect, El Nino, I have a small theory why Melbourne is not getting rain.
Houses used to have large areas of open land around them, be it a garden or a lawn. New ones certainly don't now. Much of Melbourne's open land is now covered by these houses.
Many street gutters that were bluestone with porous borders were replaces by sealed concrete.
Where one house sat on a block of land, it may have now been turned into dual occupancy with another house built on the block. All draining into the strormwater.
Creeks have been concreted. There is no seepage to surrounding land.
Might it be that Melbourne has filled up a bit too much? Doesn't the sun evaporate land moisture and then send it back down as rain? Have we covered too much of it with concrete?
Multiply that by other cities in Australia and around the around the world and I could almost give some ammo to greenhouse effect deniers.