The subtropics are geographic and climate zones located roughly between the tropics at latitude 23.5° and temperate zones north and south of the Equator.
In science and engineering the study of high pressure examines its effects on materials and the design and construction of devices, such as a diamond anvil cell, which can create high pressure. By high pressure is usually meant pressures of thousands (kilobars) or millions (megabars) of times atmospheric pressure.
A season is a division of the year marked by changes in weather, ecology, and amount of daylight. On Earth, seasons result from Earth's orbit around the Sun and Earth's axial tilt relative to the ecliptic plane. In temperate and polar regions, the seasons are marked by changes in the intensity of sunlight that reaches the Earth's surface, variations of which may cause animals to undergo hibernation or to migrate, and plants to be dormant. Various cultures define the number and nature of seasons based on regional variations.
Because Australia is a small continent, separated from polar regions by the Southern Ocean, it is not subject to movements of frigid polar air during winter, of the type that sweep over the continents in the northern hemisphere during their winter. Consequently, Australia's winter is relatively mild, with less contrast between summer and winter temperatures than in the northern continents. Seasonal highs and lows can still be considerable. Temperatures have ranged from above 50°C (122°F) to well below 0°C (32°F). Minimum temperatures are moderated.
The Southern Ocean, also known as the Antarctic Ocean or the Austral Ocean, and the "Southern Icy Ocean".</ref> comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. As such, it is regarded as the fourth largest of the five principal oceanic divisions: smaller than the Pacific, Atlantic, and Indian Oceans but larger than the Arctic Ocean. This oceanic zone is where cold, northward flowing waters from the Antarctic mix with warmer subantarctic waters.
The El Niño–Southern Oscillation is associated with seasonal abnormality in many areas in the world. Australia is one of the continents most affected and experiences extensive droughts alongside considerable wet periods. Occasionally a dust storm will blanket a region and there are reports of the occasional tornado. Tropical cyclones, heat waves, bushfires and frosts in the country are also associated with the Southern Oscillation. Rising levels of salinity and desertification in some areas is ravaging the landscape.
Drought in Australia is defined by the Australian Bureau of Meteorology as rainfall over a three-month period being in the lowest decile of what has been recorded for that region in the past. This definition takes into account that drought is a relative term and rainfall deficiencies need to be compared to typical rainfall patterns including seasonal variations. Specifically, drought in Australia is defined in relation to a rainfall deficiency of pastoral leases and is determined by decile analysis applied to a certain area. Note that this definition uses rainfall only because long-term records are widely available across most of Australia. However, it does not take into account other variables that might be important for establishing surface water balance, such as evaporation and condensation.
A dust storm is a meteorological phenomenon common in arid and semi-arid regions. Dust storms arise when a gust front or other strong wind blows loose sand and dirt from a dry surface. Fine particles are transported by saltation and suspension, a process that moves soil from one place and deposits it in another.
A tornado is a rapidly rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. The windstorm is often referred to as a twister, whirlwind or cyclone, although the word cyclone is used in meteorology to name a weather system with a low-pressure area in the center around which, from an observer looking down toward the surface of the earth, winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern. Tornadoes come in many shapes and sizes, and they are often visible in the form of a condensation funnel originating from the base of a cumulonimbus cloud, with a cloud of rotating debris and dust beneath it. Most tornadoes have wind speeds less than 110 miles per hour (180 km/h), are about 250 feet (80 m) across, and travel a few miles before dissipating. The most extreme tornadoes can attain wind speeds of more than 300 miles per hour (480 km/h), are more than two miles (3 km) in diameter, and stay on the ground for dozens of miles.
Climate change in Australia is a highly contentious political issue. Temperatures in the country rose by approximately 0.7°C between 1910 and 2004, following an increasing trend of global warming. Overnight minimum temperatures have warmed more rapidly than daytime maximum temperatures in recent years. The late-20th century warming has been largely attributed to the increased greenhouse effect. According to the Bureau of Meteorology (BOM), 80% of the land receives less than 600mm (24in) of rainfall annually and 50% has even less than 300mm (12in). As a whole, Australia has a very low annual average rainfall of 419mm (16in).
Climate change in Australia has been a critical issue since the beginning of the 21st century. In 2013, the CSIRO released a report stating that Australia is becoming hotter, and that it will experience more extreme heat and longer fire seasons because of climate change. In 2014, the Bureau of Meteorology released a report on the state of Australia's climate that highlighted several key points, including the significant increase in Australia's temperatures and the increasing frequency of bush fires, droughts and floods, which have all been linked to climate change.
Global warming is a long-term rise in the average temperature of the Earth's climate system, an aspect of climate change shown by temperature measurements and by multiple effects of the warming. Though earlier geological periods also experienced episodes of warming, the term commonly refers to the observed and continuing increase in average air and ocean temperatures since 1900 caused mainly by emissions of greenhouse gases in the modern industrial economy. In the modern context the terms global warming and climate change are commonly used interchangeably, but climate change includes both global warming and its effects, such as changes to precipitation and impacts that differ by region. Many of the observed changes in climate since the 1950s are unprecedented in the instrumental temperature record, and in historical and paleoclimate proxy records of climate change over thousands to millions of years.
The greenhouse effect is the process by which radiation from a planet's atmosphere warms the planet's surface to a temperature above what it would be without its atmosphere.
States and Territories
Australian Capital Territory (ACT)
Because of its elevation (650m (2,130ft)) and distance from the coast, the Australian Capital Territory experiences a continental climate, unlike many other Australian cities whose climates are moderated by the sea. Canberra has relatively mild and wet summers with occasional hot days occur. Canberra has cold winters with occasional fog and frequent frosts. Many of the higher mountains in the territory's south-west are snow-covered for part of the winter. Thunderstorms can occur between October and March, and annual rainfall is 623mm (25in), with rainfall highest in spring and summer and lowest in winter.
Continental climates often have a significant annual variation in temperature. They tend to occur in the middle latitudes, where prevailing winds blow overland, and temperatures are not moderated by bodies of water such as oceans or seas. Continental climates occur mostly in the Northern Hemisphere, which has the kind of large landmasses on temperate latitudes required for this type of climate to develop. Most of northern and northeastern China, eastern and southeastern Europe, central and southeastern Canada, and the central and upper eastern United States have this type of climate.
Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Fog can be considered a type of low-lying cloud, usually resembling stratus, and is heavily influenced by nearby bodies of water, topography, and wind conditions. In turn, fog has affected many human activities, such as shipping, travel, and warfare.
The highest temperature recorded in the ACT was 42.8°C (109.0°F) at Acton on 11 January 1939. The lowest temperature was −14.6°C (5.7°F) at Gudgenby on 11 July 1971.
Acton is a suburb of Canberra, ACT, Australia. Acton covers an area west of the CBD, bordered by Black Mountain to the west and Lake Burley Griffin in the south. The Australian National University campus covers most of the suburb, though also located in Acton is the National Film and Sound Archive, a branch of the CSIRO and the National Museum of Australia.
The weather in the southern half of the state is generally warm to hot in summer and cool in the winter. The seasons are more defined in the southern half of the state, especially in the South West Slopes, Central West and the Riverina regions. Rainfall usually peaks in the summer in most of parts of the state, though the Riverina region, which is in the southern-central part of the state, bordering Victoria, has drier summers and a winter rainfall peak. On a hot summer day, a southerly buster may at times moderate the extreme heat experienced in the coastal New South Wales region, from Port Macquarie southwards to Nowra.
The warmest region is the north-west, where summers are very hot, and winters cooler and drier. The weather in the northeast region of the state, or the North Coast, bordering Queensland, is hot and humid in the summer, with a rainfall peak, and mild in winter with more sunshine, and little seasonal temperature difference. The Northern Tablelands have relatively mild summers and cold winters, due to their high elevation in the Great Dividing Range.
The coldest region is the Snowy Mountains where the snow and frost continues for a long period during the winter months. The Blue Mountains, Southern Tablelands and Central Tablelands, which are situated on the Great Dividing Range, have mild to warm summers and cold winters, although not as severe as those in the Snowy Mountains. Some areas situated in or around the range, such as Bathurst, Goulburn and Bowral, among other places, have recorded freezing and/or near-freezing lows in most months of the year, unlike other places of similar latitude and altitude in the northern hemisphere.
The highest maximum temperature recorded was 49.8°C (121.6°F) at Menindee in the state's west on 10 January 1939. The lowest minimum temperature was −23.0°C (−9.4°F) at Charlotte Pass on 29 June 1994 in the Snowy Mountains. This is also the lowest temperature recorded in the whole of Australia excluding Australian Antarctic Territory.
Rainfall varies throughout the state. The far northwest receives the least, less than 180mm (7in) annually, while the east receives between 600 to 1,200mm (24 to 47in) of rain.
The Northern Territory has two distinctive climate zones. The northern end, including Darwin, has a tropical savannah climate (Köppen Aw) with high humidity and two seasons, the wet (October to April) and dry season (May to September). During the dry season nearly every day is warm and sunny, and afternoon humidity averages around 30%. There is very little rainfall between May and September. In the coolest months of June and July, the daily minimum temperature may dip as low as 14°C (57°F), but very rarely lower, and frost has never been recorded.
The wet season is associated with tropical cyclones and monsoon rains. The majority of rainfall occurs between December and March (the Southern Hemisphere summer), when thunderstorms are common and afternoon relative humidity averages over 70% during the wettest months. On average more than 1,570mm (62in) of rain falls in the north. Thunderstorms can produce spectacular lightning displays.
The rest of the territory lies in the desert centre of the country; it includes Alice Springs and Uluru, and is arid or semi-arid with little rain usually falling during the hottest months from October to March. Its seasons are more defined than the northern parts, with summers being very hot, with average temperatures often exceeding 35°C (95°F), and winters relatively cool with average minimum temperatures dipping as low as 5°C (41°F), with a few frosty nights. Central Australia receives less than 250mm (10in) of annual rainfall.
The highest maximum temperature recorded in the territory was 48.3°C (118.9°F) at Finke on 1 and 2 January 1960. The lowest minimum temperature was −7.5°C (18.5°F) at Alice Springs on 12 July 1976.
Because of its size, there is significant variation in climate across the state. Low rainfall and hot summers are typical for the inland west, a monsoonal 'wet' season in the far north, and warm subtropical conditions along the coastal strip. Inland and in southern ranges cooler temperatures are experienced, especially at nights. The climate of the coastal strip is influenced by warm ocean waters, keeping the region free from extremes of temperature and providing moisture for rainfall.
There are five predominant climatic zones in Queensland, based on temperature and humidity:
hot humid summer (far north and coastal)
warm humid summer (coastal elevated hinterlands and coastal south-east)
However, most of the Queensland populace experience two weather seasons: a winter period of rather warm temperatures with minimal rainfall, and a sultry summer period of hot, sticky temperatures and more rain.
The highest maximum temperature observed in the state is 49.5°C (121.1°F) at Birdsville on 24 December 1972. The temperature of 53.1°C (127.6°F) at Cloncurry on 16 January 1889 is not considered official; the figure quoted from Birdsville is the next highest, so that record is considered as being official.
The lowest minimum temperature is −10.6°C (12.9°F) at Stanthorpe on 23 June 1961 and at The Hermitage on 12 July 1965.
The majority of the state has the arid and semi-arid climates. The southern coastal parts of the state have a Mediterranean climate with mild wet winters and hot dry summers. The highest rainfall occurs along the southern coasts and the Mount Lofty Ranges (with an average annual rainfall of 1,200 millimetres (47in) in the vicinity of Mount Lofty); the lowest rainfall occurs in the Lake Eyre basin where the average annual totals are less than 150 millimetres (6in) and possibly even 100 millimetres (4in). Most of the rain in the southern districts of the State fall during the winter months when the sub-tropical high-pressure belt is displaced to the north over the Australian continent.
South Australia's mean temperature range is 29°C (84°F) in January and 15°C (59°F) in July. Daily temperatures in parts of the state in January and February can be up to 50°C (122°F). The highest maximum temperature was recorded as 50.7°C (123.3°F) at Oodnadatta on 2 January 1960, which is the highest official temperature recorded in Australia. The lowest minimum temperature was −8.0°C (17.6°F) at Yongala on 20 July 1976.
Tasmania has a cool temperate climate with four seasons. Summer lasts from December to February when the average maximum sea temperature is 21°C (70°F) and inland areas around Launceston reach 24°C (75°F). Other inland areas are much cooler; Liawenee, located on the Central Plateau, is one of the coldest places in Australia with February temperatures ranging between 4 to 17°C (39 to 63°F). Autumn lasts between March and May and experiences changeable weather, where summer weather patterns gradually take on the shape of winter patterns.
Victoria has a varied climate despite its small size. It ranges from semi-arid and hot in the north-west, to temperate and cool along the coast. Victoria's main land feature, the Great Dividing Range, produces a cooler, mountain climate in the centre of the state.
Victoria's southernmost position on the Australian mainland means it is cooler and wetter than other mainland states and territories. The coastal plain south of the Great Dividing Range has Victoria's mildest climate. Air from the Southern Ocean helps reduce the heat of summer and the cold of winter. Melbourne and other large cities are located in this temperate region.
The Mallee and upper Wimmera are Victoria's warmest regions with hot winds blowing from nearby deserts. Average temperatures top 30°C (86°F) during summer and 15°C (59°F) in winter. Victoria's highest maximum temperature of 48.8°C (119.8°F) was recorded in Hopetoun on 7 February 2009, during the 2009 south-eastern Australia heat wave. A screen temperature of 50.7°C (123.3°F) was recorded on 7 January 1906 in Mildura.
The Victorian Alps in the north-east are the coldest part of Victoria. The Alps are part of the Great Dividing Range mountain system extending east-west through the centre of Victoria. Average temperatures are less than 9°C (48°F) in winter and below 0°C (32°F) in the highest parts of the ranges. The state's lowest minimum temperature of −11.7°C (10.9°F) was recorded at Omeo on 13 June 1965, and again at Falls Creek on 3 July 1970.
Victoria is the wettest Australian state after Tasmania. Rainfall in Victoria increases from north to south, with higher averages in areas of high altitude. Median annual rainfall exceeds 1,800mm (71in) in some parts of the north-east but is less than 250mm (10in) in the Mallee.
Rain is heaviest in the Otway Ranges and Gippsland in southern Victoria and in the mountainous north-east. Snow generally falls only in the mountains and hills in the centre of the state. Rain falls most frequently in winter, but summer precipitation is heavier. Rainfall is most reliable in Gippsland and the Western District, making them both leading farming areas. Victoria's highest recorded daily rainfall was 375 millimetres (14.8in) at Tanybryn in the Otway Ranges on 22 March 1983.
Average annual rainfall varies from 300mm (12in) at the edge of the Wheatbelt region to 1,400mm (55in) in the wettest areas near Northcliffe, the Southwestern most tip of Australia, but in the months of November to March, although rain still falls, evaporation exceeds rainfall and it is generally very dry. Plants must be adapted to this as well as the extreme poverty of all soils. A major reduction in rainfall has been observed, with a greater number of rainfall events in the summer months. The central four fifths of the state is semi-arid or desert and is lightly inhabited with the only significant activity being mining. Annual rainfall averages about 200 to 250mm (8 to 10in), most of which occurs in sporadic torrential falls related to cyclone events in summer months.
An exception to this is the northern tropical regions. The Kimberley has an extremely hot monsoonal climate with average annual rainfall ranging from 500 to 1,500mm (20 to 59in), but there is a very long dry season of 7 months from April to November. Eighty-five per cent of the state's runoff occurs in the Kimberley, but because it occurs in violent floods and because of the insurmountable poverty of the generally shallow soils, development has only taken place along the Ord River.
Australia's tropical/subtropical location and cold waters off the western coast make most of Western Australia a hot desert with aridity a marked feature of a greater part of the continent. These cold waters produce precious little moisture needed on the mainland. A 2005 study by Australian and American researchers investigated the desertification of the interior, and suggested that one explanation was related to human settlers who arrived about 50,000 years ago.
Snowfall in the state is rare, and typically only in the Stirling Range near Albany, the southwestern-most point in WA, the only mountain range far enough south and with sufficient elevation. More rarely, snow can fall on the nearby Porongurup Range. Snow outside these areas is a major event; it usually occurs in hilly areas of south-western Australia. The most widespread low-level snow occurred on 26 June 1956 when snow was reported in the Perth Hills, as far north as Wongan Hills and as far east as Salmon Gums. However, even in the Stirling Range, snowfalls rarely exceed 5cm (2in) and rarely settle for more than one day.
The highest observed maximum temperature of 50.5°C (122.9°F) was recorded at Mardie Station on 19 February 1998. The lowest minimum temperature recorded was −7.2°C (19.0°F) at Eyre Bird Observatory on 17 August 2008.
The average annual rainfall in the Australian desert is low, ranging from 81 to 250mm (3 to 10in). Thunderstorms are relatively common in the region, with an annual average of 15 to 20 thunderstorms. Summer daytime temperatures range from 32 to 40°C (90 to 104°F); winter temperatures run 18 to 23°C (64 to 73°F).
The southern parts of Australia get the usual westerly winds and rain-bearing cold fronts that come when high–pressure systems move towards northern Australia during winter. Cold snaps may bring frosts inland, though temperatures near the coast are mild or near mild all year round. Summers in southern Australia are generally dry and hot with coastal sea breezes. During a lengthy dry spell, hot and dry winds from the interior can cause bushfires in some southern and eastern states, though most commonly Victoria and New South Wales.
The tropical areas of northern Australia have a wet summer because of the monsoon. During "the wet", typically October to April, humid north-westerly winds bring showers and thunderstorms. Occasionally, tropical cyclones can bring heavy rainfall to tropical coastal regions, which is also likely to reach further inland. After the monsoonal season, the dry season comes ("winter"), which brings mostly clear skies and milder conditions.
Rainfall records tend to be concentrated along the east coast of Australia, particularly in tropical north Queensland. The highest 24‑hour rainfall on record in Australia was 907.0 millimetres (35.7in) in Crohamhurst on 3 February 1893. The highest monthly rainfall on record was 5,387.0 millimetres (212.1in) recorded at Mount Bellenden Ker, Queensland in January 1979. The highest annual rainfall was 12,461.0 millimetres (490.6in) recorded also at Mount Bellenden Ker in 2000. Additionally, the location which receives the highest average annual rainfall in Australia is Babinda in Queensland with an annual average of 4,279.4 millimetres (168.5in).
Cold ocean currents off the coast of Western Australia result in little evaporation occurring. Hence, rain clouds are sparsely formed and rarely do they form long enough for a continuous period of rain to be recorded. Australia's arid/semi-arid zone extends to this region. The absence of any significant mountain range or area of substantial height above sea level, results in very little rainfall caused by orographic uplift. In the east the Great Dividing Range limits rain moving into inland Australia.
Australia has a compact shape, and no significant bodies of water penetrate very far inland. This is important in as much as moist winds are prevented from penetrating inland, so keeping rainfall low.
Snow at sea level is occasionally recorded on mainland Australia, but is more frequent in Tasmania where snowfalls at sea level can occur during the winter months. Snow has been recorded across most of Tasmania, though it is rare on the northern coast at sea level. Snow is rare in the southernmost capitals like Melbourne and Hobart, falling less than once every five years, and in the other capitals it is unknown (however snow has fallen in the hill suburbs of Perth and Adelaide). There are extensive, well-developed ski fields in the Great Dividing Range, a few hours' drive from Melbourne and Sydney. Light snow generally falls every winter in Canberra, and other cities that may receive regular seasonal snowfalls include Orange, Oberon, Lithgow and Katoomba in New South Wales.
The occasional cold snap, caused by cold air drifting north from Antarctica, can cause significant snowfall in rural areas, as well as major cities such as Hobart, Melbourne's outer mountain suburbs and Canberra. Such occasions are rare, but have occurred in 1958, 1965, 1986, 2005 and 2015, the 1965 event causing snow to fall as far north as Eungella, near Mackay in tropical Queensland. Extreme snow events have also produced snow as far north-west as Longreach in Queensland and in the ranges near Alice Springs, and also in lowland towns such as Dubbo and Wagga Wagga in New South Wales. The frequency and intensity of such events have been decreasing significantly over the past 40 years and the most northerly occurrence of snow in this time frame has been the Bunya Mountains in southern Queensland.
The tropical savannah zone of Northern Australia is warm to hot all year. Summers are hot in most of the country with average January maximum temperatures exceeding 30°C over most of the mainland, except for high elevations. Winters are warm in the north and cool in the south, with nightly frosts common in inland areas south of the Tropic of Capricorn. Only at the highly elevated areas do wintertime temperatures approach those found in much of Europe or North America, especially the southern parts.
Temperatures in Australia have followed an increasing trend between the years of 1910 to 2004 by approximately 0.7°C. Overnight minimum temperatures have warmed more rapidly than daytime maximum temperatures. The observed warming has hastened in recent years. The late-20th-century warming has been largely attributed to the increased greenhouse effect. Temperature differences between winter and summer are minor in the tropical region of Australia. However, they are greatest in the southern inland, with seasonal differences along the coast being moderated by the ocean's proximity. In July, a more common latitudinal distribution of average maximums is apparent, ranging from 30°C near the north coast to below 3°C in the mountainous areas of the south-east.
Average minimum temperatures in all seasons are highest in northern Australia and near the coastal areas, and are lowest in the elevated areas of the south-east. The highest average January minimum temperatures (near 27°C) are found near the north-west coast, while in winter they exceed 20°C at some coastal locations in northern Australia and on the Torres Strait and Tiwi Islands. In the mountains of New South Wales, it is not unusual to have average low minimum temperatures dipping below 5°C in January and −5°C in July. Comparatively, most inland (non-mountainous) areas south of the tropics have average July minimum between 0 and 6°C.
In the desert, the dry air and clear skies give rather large ranges in temperature between day and night. Ranges of 15°C being typical and 20°C not quite unusual. Light nighttime frosts in winter occur over much of the southern half of the arid zone, where mean July minimum temperatures are mostly in the 3 to 6°C range. Moving north, frosts become increasingly rare, with mean July minimum being around 10°C on the northern boundary.
The highest maximums in Australia are recorded in two regions, the Pilbara and Gascoyne regions of north-western Western Australia and the area extending from south-western Queensland across South Australia into south-eastern Western Australia. Many locations in this region have recorded temperatures exceeding 48°C. In January, average maximum temperatures exceed 35°C over a large area of the interior and exceed 40°C over areas in the north-west. The highest summer maximums in the Pilbara and Gascoyne average at around 41°C (in some years daily maximums consecutively exceed 40°C for several weeks at a time).
The most powerful heatwave in the history of south-eastern Australia occurred in January 1939. Adelaide (46.1°C on the 12th), Melbourne (45.6°C on the 13th) and Sydney (45.3°C on the 14th) all had record-high temperatures during this period, as did many other central district areas in New South Wales, Victoria and South Australia. The record number of consecutive days in Melbourne over 40°C is five, with Brisbane and Sydney each having two. Heatwaves usually bring by oppressively warm nights, with Oodnadatta, SA recording an Australian record of nine nights above 30°C in February 2004. Another extreme event was a prolonged period of extensive heatwaves known as the Angry Summer in early 2013.
Marble Bar achieved 160 consecutive days above 37.8°C (100.0°F) in 1923–24. Nyang had an average maximum of 44.8°C for the months of February 1998 and January 2005, an Australian record. At the other extreme, average January maximums are near 15°C on the highest peaks of the south-east ranges and near 20°C in much of Tasmania. In most of the desert region during summer, cool days are rare and usually associated with major rain events—a rather exceptional example occurred in February 1949, when many areas failed to reach 20°C on one or more days, and the maximum at Boulia, western Queensland was at 14.4°C, which was 23°C below normal.
Many other locations in Australia, except those above 500 metres, have extreme maximums between 43 and 48°C. Most Tasmanian sites away from the north coast have had extreme maximums between 35 and 40°C. The lowest extreme maximums are found along the north coast of Tasmania (e.g. 29.5°C at Low Head) and at high elevations (27.0°C at Thredbo). While extreme high temperatures are more common inland than they are near the coast, notable extreme maximum have been observed near the coast; 50.5°C at Mardie, 49.1°C at Roebourne, Western Australia, 49.4°C at Whyalla and 47.9°C at Ceduna, South Australia.
At lower elevations, most inland places south of the tropics have extreme minimum between −3 and −7°C, and these low temperatures have also occurred in locations within a few kilometres of southern and eastern coasts, such as Sale, Victoria (−5.6°C), Bega, New South Wales (−8.1°C), Grove, Tasmania (−7.5°C) and Taree, New South Wales (−5.0°C). Many locations in this region have recorded −10°C or lower, including Gudgenby in the Australian Capital Territory (−14.6°C) and Woolbrook, New South Wales (−14.5°C). In the desert, the lowest extreme minimum occur at high elevations, especially around Alice Springs, where the temperature has fallen as low as −7.5°C.
In the tropics, extreme minimum near or below 0°C have occurred at many places distant from the coast, as far north as Herberton, Queensland (−5.0°C). Some locations near tropical coasts, such as Mackay (−0.8°C), Townsville (0.1°C) and Kalumburu, Western Australia (0.3°C) have also recorded temperatures near 0°C. In contrast, some coastal locations, such as Darwin, have never fallen below 10°C, and Thursday Island, in the Torres Strait, has an extreme minimum of 16.1°C. The lowest maximum temperature on record in Australia was −6.9°C (19.6°F), recorded on 9 July 1978 at Thredbo Ski Resort in New South Wales. The highest minimum temperature on record was 35.5°C (95.9°F), recorded on 24 January 1982 in Arkaroola, South Australia and again on 21 January 2003 in Wittenoom, Western Australia.
A list of extremes can be found in the tables below:
Climatic factors contribute to Australia's high incidence of bushfires, particularly during the summer months. Low relative humidity, wind and lack of rain can cause a small fire, either man-made or caused by lightning strikes, to spread rapidly. Low humidity, the heat of the sun and lack of water cause vegetation to dry out becoming a perfect fuel for the fire. High winds fan the flames, increasing their intensity and the speed and distance at which they can travel.
Many of the worst bushfires in eastern Australia, such as the 1983 Ash Wednesday fires, accompany El Niño–Southern Oscillation events which tend to cause a warm, dry and windy climate. The worst bushfires in Australian history occurred on Black Saturday in February 2009. The human death toll of the disaster was 173, and over 2000 homes were lost.
Though Australia is generally dry and arid, the northern part is in the tropics, where rainfall can be heavy; some areas have seen world-record-breaking rain, such as the mountains southwest of Cairns. Through La Niña years the eastern seaboard of Australia records above-average rainfall usually creating damaging floods.
The 2010–2011 La Niña system broke many rainfall records in Australia, particularly in the states of Queensland and New South Wales, with extensive flooding and major damage to infrastructure and crops. The central east area of Queensland, an area the size of Germany and France combined, was under water in 2010–11. The damage could reach into the billions.
According to climate scientists, climate change is predicted by the Commonwealth Scientific and Industrial Research Organisation (CSIRO) to have significant effects on the climate of and extreme weather events in Australia, increasing temperatures and the likelihood of heat waves. According to the Bureau of Meteorology, Australia's annual mean temperature for 2009 was 0.90°C (1.62°F) above the 1961–90 average, making it the nation's second-warmest year since high-quality records began in 1910. Summers in 2013 and 2014 continued this trend of record-breaking heat—2014 was Australia's third-hottest year on record and 2013 broke national records.
In January 2013, the Bureau of Meteorology (BOM) altered its weather forecasting chart's temperature scale to include a range, coloured purple, between 52°C and 54°C.
Coastal communities face risks from sea level rise, albeit over a long period of time based on current estimates of the IPCC Fourth Assessment Report. The Gold Coast, being built on sand and with many canal developments, could be considered particularly at risk. Suburbs of Sydney like Drummoyne and Concord on rivers like the Parramatta River face risks of inundation of low-lying areas such as parks (such as Timbrell Park and Majors Bay Reserve) reclaimed from mudflats at the heads of bays, or massive expenses in rebuilding seawalls to higher levels.
Currently, there are several environmental movements urging action on climate change, including "The Big Switch", Australia's largest community climate change campaign.
New projections for Australia's changing climate include:
droughts are likely to become more frequent, particularly in the south-west
evaporation rates are likely to increase, particularly in the north and east
high-fire-danger weather is likely to increase in the south-east
Drought in Australia is defined by rainfall over a three-month period being in the lowest ten per cent of amounts having been recorded for that region in the past. This definition takes into account that low rainfall is a relative term and rainfall deficiencies need to be compared to typical rainfall patterns including seasonal variations. Specifically drought in Australia is defined in relation to a rainfall deficiency of pastoral leases and is determined by decile analysis applied to a certain area.
Historical climatic records are now sufficiently reliable to profile climate variability taking into account expectations for regions.State Governments are responsible for declaring a region drought affected and the declaration will take into account factors other than rainfall.
Australia is affected by tropical cyclones which primarily occur between December and April but have occasionally developed in November and May. Cyclones over mainland Australia occur on average five to six times each year. The regions between Broome and Exmouth are most prone to cyclones. Tropical cyclones are known to bring destructive winds, heavy rain with flooding creating storm surges along the coast, causing inundation to low-lying areas. The strongest Australian region cyclone was 2006's Cyclone Monica, with gusts topping 350km/h (220mph). Cyclones can also move inland, decaying to rain depressions, dumping heavy rain and causing flooding.
The worst cyclones of Australia have caused billions of dollars of damage and many deaths. Cyclone Tracy crossed directly over Darwin in 1974, killing 71 persons. It was Australia's most damaging cyclone.Cyclone Mahina in 1899 brought a storm surge to Far North Queensland reaching 13 metres (43ft) high, causing 400 deaths and making it the worst natural disaster to befall Australia.Cyclone Larry struck North Queensland and passed over Innisfail in 2006 causing damages estimated at A$1.5 billion. However, nobody died in that storm. Cyclone Yasi caused severe flooding and had a total estimated cost of A$3.5 billion making it the second-most costliest cyclone to strike Australia.
Blizzards are not common in mainland Australia, but occur frequently in the Snowy Mountains in New South Wales and Victoria. When blizzards do occur, they can affect the Tasmanian Highlands and, particularly, Mount Wellington, which towers over the Tasmanian capital Hobart. Blizzards do not affect any major towns or cities, because there are no populated areas located in the mountains except for the ski resort towns of New South Wales and Victoria.
A dust storm or sandstorm, a meteorological phenomenon common in arid and semi-arid regions, arises when a gust front passes or when the wind force exceeds the threshold value where loose sand and dust are removed from the dry surface. Particles are transported by saltation and suspension, causing soil erosion from one place and deposition in another.
Sandstorm usually refers to dust storms in desert areas when, in addition to fine particles obscuring visibility, a considerable amount of larger sand particles moves closer to the surface. The term dust storm is more likely to be used when finer particles are blown long distances, especially when the dust storm affects urban areas.
The United Kingdom straddles the higher mid-latitudes between 49° and 61° N. It is on the western seaboard of Afro-Eurasia, the world's largest land mass. Since the UK is always in or close to the path of the polar front jet stream, frequent changes in pressure and unsettled weather are typical. Many types of weather can be experienced in a single day. In general the climate of the UK is cool and often cloudy, and high temperatures are infrequent.
The climate of Scotland is temperate and oceanic, and tends to be very changeable, but not normally extreme. It is warmed by the Gulf Stream from the Atlantic, and given its northerly latitude it is warmer than areas on similar latitudes, for example Labrador in Canada—where the sea freezes over in winter or Fort McMurray, Canada—where −35 °C (−31 °F) is not uncommon during winter. Even though most of the country has a temperate climate, the northern islands and Highlands experience a type of weather close to the climate of the Faroe Islands or southern Norway. Scottish people sometimes describe weather which is grey and gloomy using the Scots language word dreich.
The climate of Sydney is humid subtropical, shifting from mild and cool in winter to warm and hot in the summer, with no extreme seasonal differences as the weather is moderated by proximity to the ocean, although more contrasting temperatures are recorded in the inland western suburbs. Despite the fact that there is no distinct dry or wet season, rainfall peaks in the first half of the year and is at its lowest in the second half. Precipitation varies across the region, with areas adjacent to the coast being the wettest. The city receives around 20 thunderstorms per year.
The climate of California varies widely, from hot desert to polar, depending on latitude, elevation, and proximity to the coast. California's coastal regions, the Sierra Nevada foothills, and much of the Central Valley have a Mediterranean climate, with warmer, drier weather in summer and cooler, wetter weather in winter. The influence of the ocean generally moderates temperature extremes, creating warmer winters and substantially cooler summers in coastal areas.
The climate of Delhi is an overlap between monsoon-influenced humid subtropical and semi-arid, with high variation between summer and winter temperatures and precipitation. Delhi's version of a humid subtropical climate is markedly different from many other humid subtropical cities such as Sao Paulo, New Orleans and Brisbane in that the city features dust storms and wildfire haze due to its semi-arid climate.
The climate of the north and central parts of the US state of Florida is humid subtropical. Most of South Florida has a tropical climate. There is a defined rainy season from May through October, when air mass thundershowers that build in the heat of the day drop heavy but brief summer rainfall. Late summer and early fall bring decaying tropical lows that contribute to late summer and early fall rains.
Texas' weather varies widely, from arid in the west to humid in the east. The huge expanse of Texas encompasses several regions with distinctly different climates: Northern Plains, Trans-Pecos Region, Texas Hill Country, Piney Woods, and South Texas. Generally speaking, the part of Texas that lies to the east of Interstate 35 is subtropical, while the portion that lies to the west of Interstate 35 is arid desert.
The climate in Brazil varies considerably mostly from tropical north to temperate zones south of the Tropic of Capricorn. Temperatures below the equator are high, averaging above 25 °C (77 °F), but not reaching the summer extremes of up to 40 °C (104 °F) in the temperate zones. There is little seasonal variation near the equator, although at times it can get cool enough to need to wear a jacket, especially in the rain. Average temperatures below the Tropic of Capricorn are mild, ranging from 13 °C (55 °F) to 22 °C (72 °F).
The climate of Georgia is a humid subtropical climate with most of the state having short, mild winters and long, hot summers. The Atlantic Ocean on the east coast of Georgia and the hill country in the north impact the state's climate. Also, the Chattahoochee River divides Georgia into separate climatic regions with the mountain region to the northwest being cooler than the rest of the state, the average temperatures for that region in January and July being 39 °F (4 °C) and 78 °F (26 °C) respectively. Winter in Georgia is characterized by mild temperatures and little snowfall around the state, with the potential for snow and ice increasing in the northern parts of the state. Summer daytime temperatures in Georgia often exceed 95 °F (35 °C). The state experiences widespread precipitation. Tornadoes and tropical cyclones are common.
The climate of the United States varies due to differences in latitude, and a range of geographic features, including mountains and deserts. Generally, on the mainland, the climate of the U.S. becomes warmer the further south one travels, and drier the further west, until one reaches the West Coast.
North Carolina's climate varies from the Atlantic coast in the east to the Appalachian Mountain range in the west. The mountains often act as a "shield", blocking low temperatures and storms from the Midwest from entering the Piedmont of North Carolina. Most of the state has a humid subtropical climate, except in the higher elevations of the Appalachians which have a subtropical highland climate. The USDA hardiness zones for the state range from zone 5a in the mountains to zone 8b along the coast. For most areas in the state, the temperatures in July during the daytime are approximately 90 °F (32 °C). In January the average temperatures range near 50 °F (10 °C).
The Climate of Illinois describes the weather conditions, and extremes, noted within the state of Illinois, United States, over time.
The climate of Chile comprises a wide range of weather conditions across a large geographic scale, extending across 38 degrees in latitude, making generalizations difficult. According to the Köppen system, Chile within its borders hosts at least seven major climatic subtypes, ranging from low desert in the north, to alpine tundra and glaciers in the east and southeast, humid subtropical in Easter Island, Oceanic in the south and Mediterranean climate in central Chile. There are four seasons in most of the country: summer, autumn, winter, and spring.
South Carolina has a humid subtropical climate, with hot summers and mild winters. On average, between 40 inches (1,000 mm) and 80 inches (2,000 mm) of precipitation falls annually across the state. Tropical cyclones, and afternoon thunderstorms due to hot and humid conditions, contribute to precipitation during the summer and sometimes fall months, while extratropical cyclones contribute to precipitation during the fall, winter, and spring months. Tornadoes happen mostly in the spring with a secondary peak in November. Hail and damaging winds often occur in summertime thunderstorms. Tornadoes are very uncommon in the summer unless a tropical disturbance were to spawn one.
Tasmania has a cool temperate climate with four distinct seasons. The highest recorded maximum temperature in Tasmania is 42.2 °C (108.0 °F) at Scamander on 30 January 2009, during the 2009 southeastern Australia heat wave. Tasmania's lowest recorded minimum temperature is −13.0 °C (8.6 °F) on 30 June 1983, at Butlers Gorge, Shannon, and Tarraleah.
The climate of New Zealand is varied due to the country's diverse landscape. Most regions of New Zealand belong to the temperate zone with a maritime climate characterised by four distinct seasons. The main contributing factors are the Pacific Ocean and latitude, although the mountain ranges can cause significant climate variations in locations barely tens of kilometres from each other. Conditions vary from extremely wet on the West Coast of the South Island to almost semi-arid in Central Otago and subtropical in Northland.
A humid subtropical climate is a zone of climate characterized by hot and humid summers, and cool to mild winters. These climates normally lie on the southeast side of all continents, generally between latitudes 25° and 40° and are located poleward from adjacent tropical climates. While many subtropical climates tend to be located at or near coastal locations, in some cases they extend inland, most notably in China and the United States, where they exhibit more pronounced seasonal variations and sharper contrasts between summer and winter, as part of a gradient between the more tropical climates of the southern coasts of these countries and the more continental climates of China and the United States’ northern and central regions.
The climate of Agra features a semi-arid climate that borders on a humid subtropical climate. The city features mild winters, hot and dry summers and a monsoon season. The monsoon, though substantial in Agra, is not quite as heavy as the monsoon in other parts of India. The average monsoon rainfall during June to September is 628.6 millimeters. Agra has a reputation of being one of the hottest and the coldest towns in India. In summers the city witnesses a sudden surge in temperature and at times, mercury goes beyond the 46 °C mark in addition to a very high level of humidity. During summer, the daytime temperature hovers around 46-50 °C. Nights are relatively cooler and temperature lowers to a comfortable 30 °C. Winters are bit chilly but are the best time to visit Agra. The minimum temperature sometimes goes as low as -2 or -2.5 °C but usually hovers in the range of 6 to 8 °C.
The climate of Faisalabad features a semi-arid climate (BWh) in Köppen-Geiger classification with very hot and humid summers and dry cool winters. The average maximum and minimum temperatures in June are 40.5 °C (104.9 °F) and 26.9 °C (80.4 °F). In January the average minimum and maximum are 19.4 °C (66.9 °F) and 4.1 °C (39.4 °F).
Brisbane has a humid subtropical climate with year-round period with warm to hot temperatures.
↑ CSIRO's "Climate Change Impacts on Australia and the Benefits of Early Action to Reduce Global Greenhouse Gas Emissions" "Archived copy"(PDF). Archived from the original(PDF) on 25 February 2009. Retrieved 25 January 2009.CS1 maint: Archived copy as title (link)