Do you need airconditioning in Greenmount?

Yes! Greenmount is hot! The hills are so far inland and there is a lot more tree coverage so the effect of the Fremantle Doctor is not always felt. Depend on your spot, but the hills are generally a bit hotter than the rest of Perth because of the Easterly winds that blow in after coming off the desert interior. Seems a little odd, but the wind basically blows in off the dry desert and heats up the suburbs on the outskirts of Perth. Whereas closer to the coast, the sea breezes help folks cools down in the afternoons.