Land and Resources, Climate

The climate of Australia varies greatly from region to region, with a tropical climate in the north, an arid or semiarid climate in much of the interior, and a temperate climate in the south. Despite these variations, the moderating influence of the surrounding oceans and the absence of extensive high mountain ranges help prevent marked extremes of weather. However, some areas occasionally experience extreme weather conditions, such as tropical cyclones, tornadoes, and severe drought.

Because Australia is in the Southern Hemisphere, its seasons are the reverse of those in the Northern Hemisphere. Seasonal variations, on the whole, are small. Generally, coastal and highland areas, especially in the southeast, are cooler than interior locations, and the north, particularly the northwestern coast, is the hottest region. The temperate regions of southern Australia have four seasons, with cool winters and warm summers. January and February are the warmest months, with average temperatures of between 18° and 21°C (65° and 70°F). June and July are the coldest months, with an average July temperature of about 10°C (about 50°F), except in the Australian Alps, where temperatures average 2°C (35°F). In Alice Springs, one of the few population centers in the vast arid interior of the continent, January temperatures average a daily high of 36°C (97°F), and July temperatures average a daily high of 19°C (66°F). Seasonal variations are much less pronounced in northern Australia, which has a tropical climate. This region essentially has only two seasons: a hot, wet period with heavy rainfall mainly in February and March, when the northwestern monsoons prevail; and a warm, dry interval characterized by the prevalence of southeasterly winds. In Darwin, on the northern coast, January temperatures average a daily high of 32°C (90°F), and July temperatures average a daily high of 30°C (86°F).

Australia is the driest of the inhabited continents. The arid and semiarid deserts and plains of central and western Australia encompass more than two-thirds of the continent’s area. The deserts have an annual rainfall of less than 250 mm (10 in). In most years, extensive portions of the continent experience drought conditions. However, annual rainfall is much greater in the coastal regions of northern, eastern, and southern Australia. The northern coast of Australia has a tropical monsoonal climate. Many points on the northern and northeastern coast have average annual rainfall of 1,500 mm (60 in); in some areas of the northwestern coast in Queensland, average annual rainfall exceeds 2,500 mm (100 in). Between December and April the northern coastal regions are subject to tropical cyclones, which bring high winds and torrential rains that can be destructive.

The eastern coastal lowlands receive rain in all seasons, although mostly in summer. The warm, temperate western and southern coasts receive rain mainly in the winter months, usually from prevailing westerly winds. Tasmania, lying in the cool temperate zone, receives heavy rainfall from the prevailing westerly winds in summer and from cyclonic storms in winter. Over the greater part of the lowlands, snow is unknown; however, in the mountains, particularly the Australian Alps in southern New South Wales and the northern part of Victoria, snowfall is occasionally heavy.

All of the southern states are exposed to hot, dry winds from the interior, which can suddenly raise the temperature considerably. Southeastern Australia, including Tasmania, has among the highest incidences of serious bushfires in the world, along with California in the United States and Mediterranean Europe. In 1994, notably, bushfires swept through New South Wales and destroyed several hundred homes in suburban Sydney.