Map from Google - Australia

1- Arid climate
2- Mediterranean climate (Perth, Adelaide)
3- Tropical climate (Darwin, Brisbane)
4- South-east (Canberra, Sydney, Melbourne, Hobart)
When to go
What to pack

Australia, a huge country of more than 7.5 million square kilometres (3 million square miles), crossed by the Tropic of Capricorn, has largely an arid climate, desert or semi-desert, except in the extreme north, where it is tropical with a rainy and a dry season, and the southern coasts, which have a more temperate climate, oceanic or Mediterranean. Even non-desert areas are subject to sudden increases in temperature, caused by torrid winds coming from the desert, sometimes accompanied by sand.
Being in the Southern Hemisphere, of course Australia has reversed seasons in comparison with Europe or North America.

Area with an arid climate

In the vast area generically called "Outback", the climate is arid, semi-desert where annual precipitation is between 200 and 400 millimetres (8 and 16 inches) per year (see the area within the blue line), or even desert, where precipitation drops below 200 mm (8 in) per year (inside the burgundy line).
In Australia there are several deserts, such as the Great Sandy Desert, the Gibson Desert, the Great Victoria Desert and the Simpson Desert. In this area, there are no large cities and the population density is low.
In the semi-desert area (between the burgundy and the blue line), the rains fall in the form of downpour or thunderstorm in the hottest period, at least in the north-central part, while in the southernmost part they occur mostly in winter. In the most arid area, the rains are very rare and sporadic, however, every now and then a thunderstorm may erupt, most likely in summer.
Temperatures vary depending on areas: winter is milder in the northern part, while summer is hot almost everywhere, except in the southernmost part and in the short western coastal stretch. In the north-west coast of Western Australia (see Eighty Mile Beach), the heat is intense even along the coast, for example, in Port Headland the average daily temperature in January is 31.5 °C (88.5 °F).
Here are the average temperatures in Port Hedland.
Average temperatures - Port Hedland
Port HedlandJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)262525211714121315182124
Max (°C)373637353128272932353637
Min (°F)797777706357545559647075
Max (°F)999799958882818490959799

In this coastal area the rainfall is scarce, since it amounts to about 300 mm (12 inches) per year. Here is the average precipitation.
Average precipitation - Port Hedland
Port HedlandJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec. (mm)65100452025208511215310

The sea temperature is warm all year round in Eighty Mile Beach, as you can see from the temperature of the sea at Port Hedland, which is located south of the beach, and therefore is slightly cooler in winter. Here the heat is intense from October to April.
Sea temperature - Port Hedland
Port HedlandJanFebMarAprMayJunJulAugSepOctNovDec
Sea (°C)292930292726242424252628
Sea (°F)848486848179757575777982

In Oodnadatta, in the state of South Australia, the maximum temperature exceeds 35 °C (95 °F) from December to February, but the temperature can sometimes exceed 40 °C (104 °F) from September to April, with peaks of 48/50 °C (118/122 °F) in December and January. The climate is milder from May to August, when daytime temperatures are mild, around 20 °C (68 °F), and nights can be cool or even cold (the cold records are around freezing from June to August). Here, only 180 mm (7 in) of rain per year fall.
Further north, the hot period is longer, so that highs normally exceed 35 °C (95 °F) from October to March at the Tropic of Capricorn. Some cities are located a few hundred metres (more than one thousand feet) above sea level and are therefore slightly cooler. For instance, Alice Springs, located in the Northern Territory, in the area of the MacDonnell Ranges and at 500 metres (1,650 feet) above sea level, is still hot in summer, though the highest recorded temperature is "only" 45 °C (113 °F), and it can be more easily cold in winter, when at night the temperature can drop to a few degrees below freezing, though during the day, when the sun shines, the temperature rises a lot and the air becomes pleasantly mild.
Average temperatures - Alice Springs
Alice SpringsJanFebMarAprMayJunJulAugSepOctNovDec
Min (°C)22211813854611151821
Max (°C)373633292420202328313436
Min (°F)727064554641394352596470
Max (°F)999791847568687382889397

Precipitation amounts to 250 mm (10 in) per year, mainly due to the rare showers and thunderstorms in the warm period. Here is the average precipitation.
Average precipitation - Alice Springs
Alice SpringsJanFebMarAprMayJunJulAugSepOctNovDecYear
Prec. (mm)45353010151889183040249

In Alice Springs the sun shines all year round.
Sunshine - Alice Springs
Alice SpringsJanFebMarAprMayJunJulAugSepOctNovDec
Sun (hours)101010108891010101010

The best time to visit this arid area goes from May to August: it can get cold at night, but at least you avoid the extreme heat.

Ayer's Rock

Area with a Mediterranean climate

In these two southern areas indicated on the map, the climate is Mediterranean, with mild and rainy winters, and warm and sunny summers. The proximity to the ocean makes the summer windy, but at the same time, being not far away from the desert, sometimes heat waves can occur, with highs around 40 °C (104 °F).
In Perth, Western Australia, the average temperature goes from 12 °C (54 °F) in July to 24 °C (75 °F) in January and February. In a typical year, 800 mm (31.5 in) of rain fall, most of which occur from May to August, with a maximum of 170 mm (6.7 in) in July, the central month of winter. In Perth the temperature never drops below freezing, although in the metropolitan area there may be slight frosts at night in the winter months. From November to March, the hot wind from the desert can raise the temperature to around 40 °C (104 °F) for a few days, with peaks of 45 °C (113 °F), but normally the temperature is more pleasant, with highs around 28/30 °C (82/86 °F), and sea breezes blowing from the ocean in the afternoon.
Average temperatures - Perth
Min (°C)16171512108778101214
Max (°C)313129252118171820222528
Min (°F)616359545046454546505457
Max (°F)888884777064636468727782

The ocean temperature in Perth is cool all year round, but all in all it becomes acceptable for swimming from January to May, when it reaches 22/23 °C (72/73 °F).
Sea temperature - Perth
Sea (°C)222223232221201919192021
Sea (°F)727273737270686666666870

South of Perth, in the south-western tip of Australia, in towns such as Denmark and Pemberton, the rains reach 1,000/1,200 mm (39/47 in) per year, but still with a Mediterranean pattern (ie with rainy winters and dry summers); here summers are a bit cooler, but short waves of intense heat are possible here as well.
In Adelaide, South Australia, the climate is similar to that of Perth, although summer is slightly cooler and winter is less rainy. The average temperature goes from 23 °C (74 °F) in February, to 11.5 °C (52 °F) in July. Here, too, in summer the heat of the day is cooled by sea breezes, and here too from November to March, short heat waves are possible, with peaks around 40 °C (104 °F). Here are the average temperatures.
Average temperatures - Adelaide
Min (°C)171715131088810111416
Max (°C)293027231916151719222527
Min (°F)636359555046464650525761
Max (°F)848681736661596366727781

In Adelaide, rainfall amounts to 530 mm (20.8 in) per year, with a maximum in late autumn and winter. Here is the average rainfall.
Average precipitation - Adelaide
Prec. (mm)202025457075656550403025530

In Adelaide, the sun normally shines in summer, while in winter there are sunny periods, but also cloudy periods.
Sunshine - Adelaide
Sun (hours)101097555678910

The sea in Adelaide is cooler than in Perth, as we can see in the following table. On the other hand, in the Spencer Gulf, the sea a bit warmer.
Sea temperature - Adelaide
Sea (°C)192019181817161515151718
Sea (°F)666866646463615959596364

The best times to visit these areas with a Mediterranean climate are spring and autumn, and in particular April-May and September-October, although May and September are quite rainy.

Area with a tropical climate

The vast northern area has a tropical climate, with a dry and sunny season ("the dry", usually from May to October), and a rainy and muggy season ("the wet", usually from November to April). The annual rainfall exceeds 400 mm (15.5 in), and is more abundant along the northernmost and the eastern coasts, where they exceed 1,200 mm (47 in). The tropical rains occur mainly in the form of downpour or thunderstorm, in the afternoon or evening. In the south-east, where Brisbane is located, winter is cooler, so the climate becomes sub-tropical. Vegetation is savanna-type in the driest areas, while we find rainforests in the wettest part of the north-eastern coast.
In the far north, in Arnhem Land and the Cape York Peninsula, the weather is hot, summer-like all year round, while the more you go south, the greater the difference between the seasons.
In Darwin, the capital of the Northern Territory, 1,500 mm (58.5 in) of rain per year fall, the majority of which occur from November to early April. The rainiest month is January, with almost 400 mm (15.5 in) of rain. On the contrary, from May to September it almost never rains. Here is the average precipitation.
Average precipitation - Darwin
Prec. (mm)385310255951521113501202401487

The heat is intense throughout the year, and it's muggy and sweltering in the rainy season, while it's more bearable in the dry season: from June to August, however, maximum temperatures are still around 31 °C (88 °F). Needless to say, this is the best time to visit this area.
Average temperatures - Darwin
Min (°C)252525242220192123252526
Max (°C)323232333231313133333333
Min (°F)777777757268667073777779
Max (°F)909090919088888891919191

In Darwin, the sun often shines in the dry season, while in the rainy season the sun can shine for some hours, but the sky can become cloudy with a certain frequency.
Sunshine - Darwin
Sun (hours)66791010101010987

Along the north-eastern coast, in a city like Cairns (Queensland), the rains are abundant, so that almost 2,000 mm (80 in) of rain fall annually, including more than 100 mm (4 in) from December to April. Here is the average precipitation.
Average precipitation - Cairns
Prec. (mm)3804503902159040303035501101801995

Here, too, summer is hot and humid, while winter is the driest season, but lying more to the south, the city in winter is also more temperate, since the daily average of June and July is 21 °C (70 °F).
Average temperatures - Cairns
Min (°C)242423222018171819212324
Max (°C)323131292826262728303132
Min (°F)757573726864636466707375
Max (°F)908888848279798182868890

In Cairns, the sun shines quite often throughout the year, as rainfall, though intense, generally does not last long.
Sunshine - Cairns
Sun (hours)766777789988

At some distance from the east coast of Queensland, we find the Great Barrier Reef, the world's largest coral reef, even 2,300 km (1,400 miles) long. In the north-central part of the coast, the sea is warm all year round, as we can see from the water temperatures at Cairns.
Sea temperature - Cairns
Sea (°C)292928282625242425262728
Sea (°F)848482827977757577798182

Between Cairns and Innisfail, Mount Bellenden Ker is rain-soaked, so that at its top, at 1,593 metres (5,226 feet) above sea level, even 8 metres (315 inches or 26.2 feet) of rain fall every year! Innisfail is the rainiest city in Australia, and it's the only city in the Australian tropical zone not to have a dry season, because even in winter and spring, some showers may occur: on average, 3,500 mm (138 in) of rain per year fall, with a maximum of even 660 mm (26 in) in March, and a minimum of 85 mm (3.3 in) in September and October.
Proceeding south-east along the coast, the temperature gradually decreases, therefore the climate becomes more enjoyable. In Brisbane, the capital of Queensland, summer, from November to March, is hot and moist, with some chance of thunderstorms, however the amount of sunshine is still good. Winter from June to August is very mild, with average highs around 20 °C (68 °F), lows around 10 °C (50 °F), and many sunny days; some rains are still possible even in winter, when sometimes it can get cold at night, so that the temperature can approach freezing. The average rainfall is 1,100 mm (43.5 in) per year, with a summer maximum. Every now and then, there is some risk of heavy rainfall in almost all months of the year, except maybe in August and September. In Brisbane, waves of scorching heat from the desert are more rare than in other cities of Australia, but they are still possible, from October to March.
Average temperatures - Brisbane
Min (°C)21201916131191013161819
Max (°C)292928262321202224272829
Min (°F)706866615552485055616466
Max (°F)848482797370687275818284

Near Brisbane, the sea is warm in the summer months: it exceeds 24 °C (75 °F) from December to April, so it's good for swimming, while in winter, from June to September, the sea is cool, around 21 °C (70 °F), but all in all not impossible.
Sea temperature - Gold Coast
Gold CoastJanFebMarAprMayJunJulAugSepOctNovDec
Sea (°C)262626252422212121222325
Sea (°F)797979777572707070727377

The best time to visit this area with a tropical or sub-tropical climate is winter, from June to August or September, because it's less hot and more dry.

Climate of the South-east

In the south-east, in the states of New South Wales and Victoria, the climate is temperate, with rainfall generally not abundant, but well distributed over the seasons. The weather becomes cooler in Tasmania and along the southernmost coast, but also in the hilly and mountainous regions of the extreme south-east.
Canberra, the Australian Capital, is located at 600 metres (2,000 feet) above sea level, and has an average temperature of 20.5 °C (68.5 °F) in January, and 5.5 °C (42 °F) in July. Summer is therefore not so hot, also because of the altitude, while winter is quite cold, at least by Australian standards (in fact, the winter temperatures resemble those of Madrid, Spain), and sometimes it can be foggy. In winter, frosts and even some light snowfalls are possible, but sometimes a bit of cold at night is possible even in summer. During summer, even here there can be some heatwaves, in which the temperatures rise to around 40 °C (104 °F), from November to February.
Average temperatures - Canberra
Min (°C)1313117310136911
Max (°C)282724201512111316192226
Min (°F)555552453734323437434852
Max (°F)828175685954525561667279

Rainfall is not abundant, since it amounts to 630 mm (24.7 in) per year, but the rains are fairly evenly distributed throughout the year; in late spring and summer, the rains are mainly due to thunderstorms that form in the surrounding mountainous area. Here is the average precipitation.
Average precipitation - Canberra
Prec. (mm)605555505040404555656555630

In Canberra, the sunshine amount is acceptable in winter, as there are 5/6 hours of sunshine per day even in June and July, while in summer it is good, because as mentioned the rains usually occur in the form of downpour or thunderstorm, and they do not last long.
Sunshine - Canberra
Sun (hours)1098765678999

Sydney, lying on the coast, is much milder, especially in winter: here the average temperature goes from 22 °C (71.5 °F) in January and February, to 12 °C (53.5 °F) in July. Rainfall is fairly abundant, since it amounts to 1,200 millimetres (47 in) per year, and it's more abundant from January to July, although it does not vary much in frequency (in fact, it rains on average for 8/10 days per month); in summer the rains may occur in the form of downpour or thunderstorm. The amount of sunshine is acceptable: it is neither great, nor poor, as befits a mild oceanic climate, which means that even in winter there can be sunny days. The waves of scorching heat are not so rare, and are possible from November to March, often accompanied by strong gusts of dry wind that can cause fires to spread in the hills surrounding the city.
Average temperatures - Sydney
Min (°C)181817141198911131617
Max (°C)262624221916161719222325
Min (°F)646463575248464852556163
Max (°F)797975726661616366727377

At Bondi Beach, near Sydney, the sea is pretty cool in winter, while it becomes warm enough from January to March, when it reaches 24 °C (75 °F).
Sea temperature - Sydney
Sea (°C)242424232120191919192122
Sea (°F)757575737068666666667072


Melbourne is located further south, in the state of Victoria, in a bay which opens into the strait that separates Australia from Tasmania. The latitude is still quite low, but the ocean makes the climate cool, so the average temperature goes from 20 °C (68 °F) in January to 9.5 °C (49 °F) in July. Here too, sometimes there may be waves of heat (which are more intense from November to March), though usually short-lived. Summer is usually pleasantly warm, in fact the Australian Open tennis tournament is held in January, but there'a rule called Heat Policy, for which matches are suspended with extremely high temperatures. The amount of sunshine is good but not great in summer, while it's just acceptable from May to August, with 4/5 hours of sunshine per day. The rains are not abundant, since they don't reach 600 mm (23.5 in) per year, but they are well distributed, with a relative minimum in summer.
Average temperatures - Melbourne
Min (°C)141413118766891112
Max (°C)262624201714131517192224
Min (°F)575755524645434346485254
Max (°F)797975686357555963667275

The sea temperature in Melbourne is significantly lower than in Sydney, it's also a bit lower than in Adelaide, and remains quite cool even in the summer months.
Sea temperature - Melbourne
Sea (°C)181918171615131313141516
Sea (°F)646664636159555555575961

In south-eastern Australia, between Melbourne and Canberra, there is a mountain range, the Australian Alps, culminating in Mount Kosciuszko, which is Australia's highest mountain, with its 2,228 metres (7,310 feet). This area is humid and rainy, cold in winter, even snowy above 1,500 metres (5,000 feet), and cool in summer.
There are also resorts equipped for winter sports. Here are the average temperatures of Thredbo, located at 1,400 metres (4,600 feet) above sea level.
Average temperatures - Thredbo
Min (°C)77420-3-4-3-1135
Max (°C)212118141065610131619
Min (°F)454539363227252730343741
Max (°F)707064575043414350556166

Further south we find Tasmania, the southernmost island, exposed to the westerly winds, which has an oceanic climate, albeit mild; rainfall is more abundant in the west, where it exceeds 1,200 mm (47 in) per year. The capital, Hobart is located in the eastern part, and receives only 570 mm (22.5 in) of rain, however, well distributed throughout the year, and occurring as frequent short showers and drizzles.
The average temperature goes from 8.5 °C (47.5 °F) in July, to 17.5 °C (63.5 °F) in January and February, so winter is mild and summer is cool. Anyway, every now and then during winter a cold air mass can reach the island, and snowfall can occur in inland hills and mountains, while in summer even Tasmania can sometimes be reached by the hot desert wind, although here this wind comes generally weakened.
Average temperatures - Hobart
Min (°C)13131198556781011
Max (°C)222220181512121415171920
Min (°F)555552484641414345465052
Max (°F)727268645954545759636668

The temperature of the sea in Tasmania is cold all year round, and it reaches at most 17 °C (63 °F) from January to March in the southern part (see Hobart), and 18 °C (64 °F) in the north.
Sea temperature - Hobart
Sea (°C)171717161514131313131415
Sea (°F)636363615957555555555759

This area of south-east Australia can be visited in spring and autumn, that is in April-May and September-October (or even March-April and October-November in Tasmania), with a preference for the latter, because autumn (April-May) it's often rainy.

Australia can be affected by tropical cyclones, intense low pressure areas that are formed when the sea is very warm, and therefore it's able to provide the necessary energy. Cyclones bring strong winds and torrential rains, and affect mainly the northern coasts, although sometimes they can penetrate in inland areas (especially in Western Australia), weakening along the way but still bringing heavy rains. Cyclones are generally formed between mid-November and mid-May, but the phenomenon is more likely from January to mid-April.
In the following image we can see the areas that have been affected by cyclones in the period 1950-2005 (the points refer to the eye of the cyclone, so the affected area is larger).

Area affected by cyclones in Australia

Australia's climate is affected also by the phenomenon known as El Niño, which is associated with more or less severe drought throughout the country, particularly along the north and east coast, where it reduces the summer rains, and in the south, where drought is accompanied by hot winds from the desert which can cause fires. The opposite phenomenon, La Niña, brings rains more abundant than usual in the north and east, especially in spring and summer, and an increase in the number of cyclones.

If you plan to visit the whole country, not just the south but also the vast arid outback and the tropical north, you may prefer winter, from June to August, to avoid the heat, which can be intense in the other seasons, especially in the north-central, and in summer in the south, but also to avoid the rains (and sometimes cyclones) that can affect the north in summer. Of course, winter in the south is quite cold, it can be very rainy in Perth and in western Tasmania, but if you don't like the heat this is the best solution.
If you intend to visit mainly the southern areas, where the major cities are located, and maybe you want to make a quick tour in the central and northern regions, trying to avoid the heat as much as possible, you can choose spring and autumn, and in particular April-May and September-October.
The southern areas can be visited also in late spring and summer, especially in November-December in Sydney, and from November to February in Melbourne, taking into account that sometimes there may be some scorching days.

In winter (June to August). In the tropical north and Darwin, lightweight clothing of natural fibres, sun hat, a scarf for the breeze, a light sweatshirt for the evening and air-conditioned places.
In the desert, spring/autumn clothes, light for the day, sweater, wind jacket, warm jacket for the night, scarf for the sand.
In the north-east (see Cairns, Innisfail), light clothes for the day, a sweatshirt for the evening, possibly a raincoat for the rain showers; for the reef, equipment for snorkeling, water shoes or rubber soled shoes.
In the centre and south and the major cities, spring/autumn clothes, sweater, warm jacket for the evening and for windy days, raincoat or umbrella. In the southern mountains, warm clothes, fleece, down jacket, gloves. In Canberra and Tasmania, warm clothes, sweater, down jacket, hat.

In summer (December to February). In the tropical north and Darwin, and in the north-east down to Brisbane, lightweight clothing of natural fibres, a scarf for the breeze, a light sweatshirt for the evening and for air-conditioned places, a light raincoat for thunderstorms; for the reef, equipment for snorkeling, water shoes or rubber soled shoes.
For the desert, lightweight clothing, loose-fitting and made of natural fabric (cotton or linen), desert turban, sunglasses, a light sweatshirt for the evening, a sweatshirt for the night, sleeping bag for overnight stays outdoors, desert boots.
In the centre and south and the major cities, light clothing, a sweatshirt for the breeze and for cool days, a scarf for the wind-borne sand and dust, possibly a light jacket and an umbrella, especially in Canberra, Sydney and Melbourne. For Tasmania, spring/autumn clothes, sweater, jacket.