Australia is the driest inhabited continent by average annual precipitation. The Australian mainland receives about 470 millimetres of rain per year on average, although rainfall varies greatly between regions and from year to year.
Much of Australia’s interior is desert or semi-arid, including large areas of the Great Victoria, Great Sandy and Simpson deserts. Roughly 70% of the country is classified as arid or semi-arid, and deserts cover about 18% of its land area. The continent’s position near the subtropical high-pressure belt helps produce descending, dry air across its interior.
Australia is not uniformly dry. Tropical northern regions can receive heavy monsoonal rain, while parts of the northeast coast and Tasmania are comparatively wet. Rainfall is also strongly influenced by El Niño, the Indian Ocean Dipole and other climate patterns, producing alternating droughts and floods. Antarctica is far drier overall, but it is not considered an inhabited continent in this comparison.