How does rainfall change from Australia’s coast toward the inland?

Australia is an arid continent where rainfall patterns are heavily influenced by its geography, with the highest precipitation occurring along the coastal fringes and decreasing significantly toward the interior.12

In the north, east, southeast, and southwest coastal regions, rainfall is generally adequate to support vegetation. The eastern and northern coasts receive the heaviest rains, often driven by tropical cyclones, monsoons, and the interaction between trade winds and the Eastern Uplands, which create a rain shadow effect. Consequently, areas inland of these ranges, such as the Murray plains, receive substantially less annual rainfall than the coastal zones.12

As one moves into the vast interior, the climate becomes increasingly arid. Over two-thirds of the continent receives less than 20 inches (500 mm) of rain annually, and over one-third receives less than 10 inches (250 mm). This interior region, often referred to as the Outback, is characterized by unreliable and episodic rainfall, with long periods of drought frequently interrupted by intense, flooding rains.21