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Australian weather and seasons – a variety of climates

Australia is a continent that experiences a variety of climates due to its size. The temperature can range from below zero in the Snowy Mountains in southern Australia to extreme heat in the Kimberley region in the north-west of the continent.

Due to the size of the continent, there is not one single seasonal calendar for the entire continent. Instead there are six climatic zones and this translates as two main seasonal patterns.

There is a Summer / Autumn / Winter / Spring pattern in the Temperate zone, also affecting the Desert and the Grassland climatic zones and, a Wet / Dry pattern in the tropical north which includes the Equatorial, Tropical and sub-tropical zones.

Depending upon where you are each Month, the season will vary on whether the weather is defined by the Temperate zone seasons or the tropical seasons.

Bureau of Meteorology, major climatic zones

Climatic zones

The temperate zone: a Summer / Autumn / Winter / Spring pattern

The Temperate zone occupies the coastal hinterland of New South Wales, much of Victoria, Tasmania, the south-eastern corner of South Australia and the south-west of Western Australia

The seasons in the temperate zone are described in terms of European seasons applied to the southern hemisphere in the following sequence:

  • Summer: December to February
  • Autumn: March to May
  • Winter: June to August
  • Spring: September to November

This means that the Australian Christmas takes place at the height of summer. It also means that the mid-year break for students happens in winter. The long end of year break for students is commonly known as the 'summer holidays', or the 'Christmas holidays'.

Natural temperate grasslands, Queanbeyan Nature Reserve, New South Wales

The two other zones affected by the temperate seasons are:

  • Grasslands (or savanna) – essentially a belt surrounding the arid and semi-arid desert areas in the centre and seeping into the area north of Alice Springs in the Northern Territory
  • Desert – arid and semiarid areas of the centre of the continent, stretching across the vast amount of South Australia and Western Australia, far south western Queensland and far north western corner of New South Wales, and not quite half of the Northern Territory

The tropical zones: a Wet / Dry pattern

There are three climatic zones in the tropical areas of Australia:

  • Equatorial – the tip of Cape York and Bathurst and Melville Islands north of Darwin
  • Tropical – across northern Australia including Cape York, the Top End of the Northern Territory, land south of the Gulf of Carpentaria, and the Kimberley region
  • Sub-tropical – the coastal and inland fringe from Cairns along the Queensland coast and hinterland to the northern areas of New South Wales and the coastal fringe north of Perth to Geraldton in Western Australia.

Approaching cyclonic storm east of the Serpentine Lakes, Great Victoria Desert, on the border of South Australia and Western Australia. Image courtesy of CSIRO Land and Water.

The wet and dry seasons

The tropical regions of Australia, in the north of the country, including the equatorial and sub-tropical zones have high temperatures and high humidity and distinct wet and dry seasons.

In the Australian tropics the wet season, called the monsoon season, lasts about six months, between November and March. It is hotter than the dry season, with temperatures between 30 and 50 degrees Celsius. This is because of the high humidity during the wet, which is caused by large amounts of water in the air. During the wet there is a lot of rain, which frequently causes flooding.

The dry season lasts about six months, usually between April and October. Temperatures are lower and the skies are generally clearer during the dry. The average temperature is around 20 degrees Celsius

The 'build up' is the humid time of year between the wet and dry seasons. It usually lasts for three or four months. Things become quite tense during the 'build up' as people sit and swelter in the humidity while waiting and hoping for the first rains to come. The humidity continues day and night with no respite, so when the rains finally do come everyone enjoys their cooling relief.

Temperature

Bureau of Meteorology, Maximum temperature

In the southern capital cities: Sydney, Canberra, Melbourne, Hobart, Adelaide and Perth, defined by the temperate zone, the average temperatures are: Summer minimum 16 and Summer maximum 26 and Winter minimum 6 and Winter maximum 14, all in degrees Celsius.

In the sub-tropic and tropical cities the average minimum temperatures are: Brisbane 16 and Darwin 23 with the average maximums: Brisbane 25 and Darwin 32. In the inland city of Alice Springs, surrounded by desert and grassland, the average minimum is 20 and the average maximum is 32.

Summer heat waves and sea temperature

Since the 1950s, Australian temperatures have, on average, risen by about 1°C with an increase in the frequency of heat waves and a decrease in the numbers of frosts and cold days, except in the regions immediately to the west and north-west of Sydney.

Since 1900, the sea temperatures are showing to be two degrees warmer.

Indigenous seasonal calendars

Indigenous people's knowledge about the weather, and their descriptions of the seasons and climatic conditions is recognised today in work with scientists and the Australian Bureau of Meteorology (BOM).

For the Jawoyn people, from around Katherine near south east Arnhem Land in the Northern Territory, six seasons are described in the tropical zone in which they live. These descriptions can be useful as they are more detailed in their description and therefore more informative about what weather is like to experience.

Mataranka tropical pool, Northern Territory

  • January: Summer (temperate zone), Wet (tropical zone), Jiorrk, the wet season
  • February: Summer (temperate zone), Wet(tropical zone) Jiorrk, the wet season
  • March: Autumn(temperate zone), Wet(tropical zone) Bungarung, the end of the rains
  • April: Autumn(temperate zone), Dry (tropical zone) Bungarung, the end of the rains
  • May: Autumn (temperate zone), Dry (tropical zone) Jungalk, the hot start of the dry
  • June: Winter (temperate zone), Dry (tropical zone) Jungalk, the hot start of the dry
  • July: Winter(temperate zone), Dry (tropical zone), Malaparr, the cooler, dry
  • August: Winter (temperate zone), Dry (tropical zone), Malaparr, the cooler, dry
  • September: Spring (temperate zone), Dry (tropical zone), Worrwopmi, the humid time
  • October: Spring (temperate zone), Dry (tropical zone), Worrwopmi, the humid time
  • November: Spring (temperate zone), Wet (tropical zone), Wakaringding, the first rains
  • December: Summer (temperate zone), Wet (tropical zone), Wakaringding, the first rains

Rainfall

Bureau of Meteorology, Australian Rainfall Analysis June 2010-May 2013

Cyclones, snow and floods

The tropics are affected by the extremes of cyclones in the wet season and the inland deserts can remain totally dry for years whilst rains can produce floods. The wettest months in the southern capitals are from May to July.

Along the Great Dividing Range the mountain range that passes through New South Wales and Victoria, there are regular winter snowfalls. The snow season in the Alps in south-eastern Australia is June to September.

The tradition of observational practice and high quality records have contributed to a vast amount of data now held and shared by the Bureau of Meteorology (BOM). Based on over 200 years of data, the Bureau has observed that Australia's climate is changing, and observes the following trends:

  • Since 1900, there have been many disastrous floods, with 2011, the year of the Queensland, Brisbane and Victorian floods, recorded as the second wettest year on record
  • Overall, rainfall patterns have also changed – the northwest has seen an increase in rainfall over the last 50 years while much of eastern Australia and the far southwest have experienced a decline.
    (Bureau of Meteorology, A hundred years of science and service, 2001, pp 11-15)

Cyclones

Cyclone Yassi hits Townsville, 2011, Climate Commission

Cyclones are a tropical weather phenomenon. They are usually encountered in Australia between November and April, and they mostly take place in the north of the country. The Western Australian and Northern Territory coasts, as well as the Queensland coast, are the usual places that cyclones occur.

About six cyclones happen in Australia every year. By far the most famous cyclone in Australia is Cyclone Tracy, which hit Darwin in the Northern Territory on Christmas Eve 1974. Forty-nine people died as a result, and over 600 people were injured. Darwin had to be evacuated because over eighty per cent of the city was destroyed. But Tracy is not the worst cyclone to ever visit Australia. In 1899, Cyclone Mahina killed over 400 people when it destroyed an entire pearl-fishing fleet at Bathurst Bay in Queensland.

The dry regions the desert

Trees shaped by the weather along a track near Margaret River crossing, c1920. Image courtesy of National Library of Australia: an24431083.

The driest regions of Australia are found mostly in central Australia, in the arid and semi-arid desert regions with high daytime temperatures and low amounts of rain.

The dry desert regions of Australia are characterised by intense heat during the day and intense cold at night. Temperatures range from around 40 degrees celsius in the summer to between 16 and 24 degrees celsius in the winter. At night the temperature can vary from 19 degrees Celsius to zero degrees Celsius.

Drought

Desert conditions are different from drought.A drought is an unusually long period of time when there is not enough water for people to use in the way they normally would.

There have been many serious droughts in Australia in the last 200 years. The 18951903 drought lasted eight years and caused the death of half of Australia's sheep and forty per cent of its cattle. The 1963–68 drought caused a forty per cent reduction in wheat crops across Australia. In central Australia that same drought actually lasted eight years, from 1958 to 1967.

Predicting climate and weather patterns

Climate predictions and long range weather forecasting have improved the ability and capacity to respond to natural disasters in Australia:drought, bushfires, cyclones, floods and severe storms experienced in Australia. Today, weekly, monthly, seasonal and annual updates on the national, territory and climatic zones are provided with data presented as trends since 1900.

Storm cloud near Millthorpe, NSW, Image by Rose Toomer. Bureau of Meteorology.

The ability to provide accurate forecasts and warnings for rainfall, floods and tropical cyclones has helped mitigate and lessen the loss of lives in natural disasters. This was seen in the response to Cyclone Yasi in 2011, very different to the response to Cyclone Larry in 2009 and Cyclone Tracy in 1974, where forty-nine people died, and over 600 people were injured.

El Niño-Southern Oscillation index

The great Australian droughts of the twentieth century have mostly been closely linked with the major swings in the Southern Oscillation Index (SOI) with drought in eastern Australia coinciding with the El Niño (warm central and eastern Pacific Ocean) phase of the El Niño-La Niña cycle. (Bureau of Meteorology, A hundred years of science and service, 2001, p.14)

The Bureau provides information on the seas surface, trade winds and ocean temperatures, Today, the Bureau provides statements and reports about the El Niño-Southern Oscillation index,

a measure of fluctuations in the surface pressure difference between Tahiti and Darwin and a useful indicator of the broad scale controls on Australian weather.

A weather balloon launch at Giles weather station, image ABC.

2010, the National Environmental Information Infrastructure, a digital network

Research and analysis has shown that understanding the inter-connections and natural linkages within the environment, can reveal much about climate and weather.

Established in 2010, the National Environmental Information Infrastructure, a digital network, is designed to monitor, detect and develop environmental information as it relates to climate and aims to improve the Bureau of Meteorology's capacity to predict change.

 

Useful links

Look, listen and play

Current meteorology information

Research

Weather phenomena

Weather knowledge

Weather station networks

References

  • Alan Reid, Banksias and Bilbies - Seasons of Australia, 1995.
  • Bureau of Meteorology, A hundred years of science and service, 2001

Last updated: 29 June 2013
Creators: Kathryn Wells

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