Australia's climate is governed largely by its size and by the hot, sinking air of the subtropical high pressure belt. This moves north and south with the seasons. But it is variable, with frequent droughts lasting several seasons -- thought to be caused in part by the El Nino-Southern Oscillation. The climate varies widely due to its large geographical size, but by far the largest part of Australia is desert or semi-arid. Only the south-east and south-west corners have a temperate climate and moderately fertile soil. The northern part of the country has a tropical climate, varied between tropical rainforests, grasslands and desert.

Answer this question: most of australia has one of the what climates? Let's give stream of consciousness first:
This is the relevant information: The climate varies widely due to its large geographical size, but by far the largest part of Australia is desert or semi-arid.
So, the final answer is desert or semi-arid.