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.
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’.
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.
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.