The climate of Australia varies widely, but by far the largest part of Australia is desert or semi-arid – 40% of the landmass is covered by sand dunes. 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, part desert. Australia’s climate is ruled by the hot, sinking air of the subtropical high pressure belt which moves north and south with the seasons. This causes the rainfall pattern over Australia to be highly seasonal. In many parts of the country, seasonal high and lows can be great with temperatures ranging from above 50 °C (122 °F) to well below zero. Minimum temperatures are moderated by the lack of mountains and the influence of surrounding oceans.

Since it’s a small continent separated from polar regions by the Southern Ocean, Australia doesn’t get the harsh snaps of polar air that swarm over Northern Hemisphere continents during winter. The continents in the Northern Hemisphere have a considerable temperature contrast between summer and winter, whereas in most of Australia the temperature contrast between summer and winter isn’t very great.

Australia’s rainfall is the lowest of the seven continents (besides Antarctica). Rainfall is variable, with frequent droughts lasting several seasons and is thought to be caused in part by the El Niño-Southern Oscillation. The El Niño-Southern Oscillation is associated to seasonal abnormality in many areas in the world, though Australia is one of the most affected continents, which experiences extensive droughts alongside with considerable wet periods.

Abundance of tropical cyclones, heat waves, bushfires and frosts in the country are also associated to the Southern Oscillation. Occasionally a dust storm will blanket a region or even several states and there are reports of the occasional large tornado. Rising levels of salinity and desertification in some areas is ravaging the landscape. According to the Bureau of Meteorology, 80% of the land have a rainfall less than 600 mm (24 in) per year and 50% having even less than 300 mm (12 in).

Australia’s tropical/subtropical location and cold waters off the western coast make most of Western Australia a hot desert with aridity a marked feature of a greater part of the continent. These cold waters produce precious little moisture needed on the mainland. A 2005 study by Australian and American researchers investigated the desertification of the interior, and suggested that one explanation was related to human settlers who arrived about 50,000 years ago. Regular burning by these settlers could have prevented monsoons from reaching interior Australia.

The average annual rainfall in the Australian desert is low, ranging from 200 to 250 mm (8 to 10 in) per year. Thunderstorms are relatively common in the region, with an average of 15 – 20 thunderstorms per annum.[3] Summer daytime temperatures range from 32 to 40 °C (90 to 104 °F). In winter, this falls to 18 to 23 °C (64 to 73 °F).

This text is drawn from Wikipedia