What is arid climate?

Arid climate in Australia is characterised by very low rainfall, high temperatures, and high evaporation rates, covering most of the continent's interior. About 18 per cent of Australia is classified as arid desert and another 50 per cent or so is semi-arid grassland, making the country the second-driest continent on Earth after Antarctica.

The arid zone receives less than 250 millimetres of rain a year and experiences extreme temperature swings, with summer maximums regularly above 40 degrees Celsius and winter overnight minimums often near freezing. Settlements such as Alice Springs in the Northern Territory and Coober Pedy in South Australia have recorded daytime highs above 45 degrees Celsius. The highest reliable temperature recorded in Australia is 50.7 degrees Celsius at Onslow, Western Australia, on 13 January 2022.

Rainfall in the arid zone is unpredictable and highly variable. Years of drought may be followed by a single major downpour that fills inland river systems and creates spectacular wildflower displays. Lake Eyre / Kati Thanda, Australia's largest lake when full and the lowest natural point on the continent at 15 metres below sea level, only fills properly every few decades, most recently in 2010 and 2024.

Despite the harsh climate, the arid zone supports unique ecosystems and cultures. Spinifex grasslands cover huge areas, and species such as the bilby, the marsupial mole, and the central rock-rat are adapted to the conditions. Aboriginal peoples have lived in the arid zone for at least 50,000 years, developing intimate knowledge of soakages, water trees, and seasonal food resources. Modern industries include cattle and sheep grazing on stations covering thousands of square kilometres, mining (notably opal at Coober Pedy and uranium at Olympic Dam), and outback tourism.