Australia Geography: Climate

The Dry Continent

The climate in Australia is varied and ranges from topical to sub alpine. Australia is also the oldest landmass on earth and the most eroded of all continents, the nearby island state of Tasmania being the exception. This vast landmass is also the most stable of all continents, with few major fault lines.

This means that Australia lacks high mountains such as what you find in neighboring New Zealand. However all the eons of erosion have formed some of the strangest geographical features on earth, such as Ayers Rock in the Northern Territory, or the Bungle Bungles Mountains and The Pinnacles of Western Australia.

Australia is also the driest inhabited continent on earth, but the eastern seaboard where the majority of the population is concentrated, is a lush and fertile area, with a climate ranging from temperate to tropical. The main mountain range is known as the Great Dividing Range or Eastern Highlands. This long mountain chain separates the green eastern seaboard from the barren Outback.

The southern end of the Great Dividing Range has an area known as the Snowy Mountains, or otherwise known as the Australian Alps. This area actually receives more snow than Switzerland, and is the only area suitable for skiing in Australia. Australia also contains many pockets of tropical and temperate rain forest on the eastern coast, but the predominate forest in Australia is Eucalypti forest.

The southwest corner of Western Australia has a Mediterranean climate and the Northern regions of this continent have areas of Rainforest and below that are large areas of savanna grasslands. Tasmania, the island state in the south has large areas of temperate wilderness and steep mountains.

Australian seasons are the antithesis of those in Europe and North America. It's hot in December and many Australians spend Christmas at the beach, while in July and August it's midwinter. Summer starts in December, autumn in March, winter in June and spring in September.

Other Aspects of Climate

Heat waves

Periods with a number of successive days having a temperature higher than 40øC are relatively common in summer over parts of Australia. With the exception of the north-west coast of Western Australia, however, most coastal areas rarely experience more than three successive days of such conditions.

The Kimberley district of Western Australia is the consistently hottest part of Australia in terms of annual average maximum temperature. Wyndham, for example, has an annual average maximum of 35.6øC.

Frost

The frequency of frost, which can cause serious losses of agricultural crops, depends on a number of factors. In coastal areas the relatively warm ocean temperatures ameliorate those on land, while distance from the Equator and elevation above sea level are major cooling influences.

Parts of Australia most subject to frost are the eastern uplands from north-eastern Victoria to the western Darling Downs in southern Queensland where there may be more than ten nights a month with readings of 0øC (or under).

Humidity

Australia is a dry continent in terms of the water vapor content or humidity of me air. Moisture content can be expressed by a number of parameters. The most commonly known is relative humidify. It can be thought of as the relative evaporating power of the, air; when the humidity is low, a wet surface, like our skin, can evaporate freely. When it is high, evaporation is retarded. People cancel this as discomfort or even stress as the body's ability to perspire (and hence cool) decreases with increasing relative humidity. The combination of high temperature and high humidity is potentially dangerous for people who are active in such conditions.

Sunshine

Sunshine here refers to bright or direct sunshine. Australia receives relatively large amounts of sunshine although seasonal cloud formations have a notable effect on its spatial and temporal distribution. Cloud cover reduces both incoming solar radiation, and outgoing long wave radiation and thus affects sunshine, air temperature and other climatic elements on the Earth's surface.

Most of the continent receives more than 3,000 hours of sunshine a year, or nearly 70% of the total possible.

Droughts

Drought, in general terms, refers to an acute deficit of water supply to meet a specified demand. Demands for water are very diverse, hence the actual declaration of drought conditions for an area will generally also depend on the effects of a naturally occurring water deficit on the principal local industries.

Since the 1860s there have been ten major Australian droughts. Some of these major droughts could be described as periods consisting of a series of dry spells of various lengths, overlapping in time and space, and totaling up to about a decade.

Winds

The mid-latitude anticyclones are the chief determinants of Australia's two main prevailing wind streams. In relation to the west-east axes of the anticyclones these streams are easterly to the north and westerly to the south.

Perth is the windiest capital with an average wind speed of 15.6 km/h; Canberra is the least windy with an average wind speed of 5.4 km/h. The highest wind speeds and wind gusts recorded in Australia have been associated with tropical cyclones: The highest recorded gust was 267 km/h at Learmonth, Western Australia on 22 March 1999 (occurring with Tropical Cyclone Vance).

Fog

The formation of fog depends on the occurrence of favorable meteorological elements - mainly temperature, humidity, wind and cloud cover. The nature of the local terrain is important for the development of fog and there is a tendency for this phenomenon to persist in valleys. The incidence of fog may vary significantly over distances as short as one kilometer.

Fog in Australia tends to be more common at the south than the north, although parts of the east coastal areas are relatively fog-prone even in the tropics.

Floods

Widespread flood rainfall may occur anywhere in Australia, but it has a higher incidence in the north and in the; eastern coastal areas. These flood rains are notably destructive. Although chiefly caused by summer rains, they may occur in any season.