Annual climate statement 2020
Australia’s climate in 2020
Australia's fourth-warmest year on record, with a move from drought and fire to La Niña
2020 was Australia's fourth-warmest year on record. Australia's area-averaged mean temperature for 2020 was 1.15 °C above the 1961–1990 average. Mean maximum temperatures were the eighth-warmest on record at 1.24 °C above average. Mean minimum temperatures were the fourth-warmest on record at 1.05 °C above average. The national temperature dataset commences in 1910.
The mean temperature for the 10 years from 2011 to 2020 was the highest on record, at 0.94 °C above average, and 0.33 °C warmer than the 10 years 2001–2010. All years since 2013 have been amongst the ten warmest on record for Australia. Of the ten warmest years, only one (1998) occurred before 2005. Australia's climate has warmed on average by 1.44 ± 0.24 °C since national records began in 1910. Most of this warming has occurred since 1950.
Annual mean temperatures for 2020 were above average for the majority of Australia, with close to average annual mean temperatures for parts of eastern South Australia, and the west of Victoria and New South Wales. It was the second-warmest year on record for Western Australia as a whole, the fifth-warmest for the Northern Territory and Queensland.
Rainfall for Australia was close to average for the nation as a whole at 483.4 mm; 4% above the 1961–1990 average of 466.0 mm. The national rainfall dataset commences in 1900.
Following Australia's driest year on record in 2019, at the start of 2020 there were significant rainfall deficiencies in place across much of Australia. While water storages in the southern Murray–Darling Basin saw significant increases during 2020, storage levels in the northern Basin despite showing some increases, remained low at the end of the year.
Rainfall for the year was below to very much below average for some parts of Australia, including in southeastern Queensland, the west and southwest of Western Australia, and western Tasmania.
Annual rainfall was above average across large parts of New South Wales, parts of South Australia between the Flinders Ranges and Lake Eyre / Kati Thanda, and much of northern and eastern Western Australia, and much of the Northern Territory.
The El Niño–Southern Oscillation was neutral during the first half of 2020. La Niña became established during September, and reached moderate strength by the end of the year. The Southern Annular Mode also influenced Australian climate during 2020. It favoured reduced rainfall over southwest Western Australia, southern Victoria, and Tasmania during May and June, enhanced rainfall across much of southern Australia during much of August, and reinforced the wet La Niña signal in early November and much of December.
Most capital cities were warmer than average in 2020.
Daytime temperatures were especially warm for Sydney, Hobart and Darwin, with the mean maximum temperature well above average. The annual mean maximum temperature was also above average for Perth, Canberra, and Brisbane, close to average at most sites across greater Adelaide, and close to average or slightly below average at most sites across greater Melbourne.
All of the capital cities, except Adelaide, observed warmer than average annual mean minimum temperatures. Nights were especially warm in Sydney, Darwin, Hobart, Canberra, and Brisbane. Annual mean minimum temperatures were slightly above average at most sites across greater Melbourne. For Adelaide (West Terrace / ngayirdapira) the annual mean minimum temperature was close to average, with most sites across the greater Adelaide region within half a degree of average, some warmer than average and some cooler.
Rainfall was close to average for Darwin, Brisbane, and Hobart, and close to average at most sites across greater Adelaide. Perth had lower than average rainfall for the year, while annual rainfall was well above average for Melbourne, Canberra, and Sydney.
Table of annual rainfall, temperature and sea surface temperatureTable of annual national rainfall, temperature, and sea surface temperature anomalies and ranks
Australia's fourth-warmest year on record
2020 was Australia's fourth-warmest year on record, with the annual national mean temperature 1.15 °C above average. Australia's warmest year on record was 2019 at 1.52 °C above average, well above the second warmest: 1.33 °C above average in 2013.
Warmth was widespread and persistent throughout 2020—January, February, April, June, August, September, and November were all amongst the ten warmest on record for Australian mean temperature for their respective months. Both November and spring as a whole were warmest on record.
Annual mean temperatures were above or very much above average for most of Australia. They were in the highest 10% of historical observations for most of Western Australia, the Northern Territory, Queensland, and along the coast of New South Wales and far eastern Victoria. It was amongst the five warmest years on record for Queensland, Western Australia, and the Northern Territory. For eastern South Australia, western Victoria, and southwestern New South Wales annual mean temperatures were close to average.
Maximum temperatures for the year were also well above average across most of Australia, but close to average for much of the inland southeast away from the east coast. They were in the highest 10% of historical observations for most of Western Australia, the Northern Territory, and Queensland away from the southwest. Annual mean maximum temperatures were amongst the ten warmest on record for Queensland, Western Australia, and the Northern Territory.
Annual mean minimum temperatures were also above average for much of the country, but close to average for eastern South Australia, northwestern Victoria, and southwestern New South Wales. Annual mean minimum temperatures were in the highest 10% of historical observations for much of Western Australia except the Kimberley and parts of the south and west coast; western South Australia; much of the Northern Territory; much of Queensland; eastern New South Wales and far eastern Victoria. Annual mean minimum temperatures were amongst the ten warmest on record for Queensland, New South Wales, Western Australia, and the Northern Territory.
December 2019 had been marked by extreme heat and dangerous fire weather conditions. A large number of fires had started across eastern Australia during spring, and in the absence of widespread rainfall, the fires continued to burn across a large area of southeast Queensland, eastern New South Wales, and northeastern Victoria and Gippsland. The last days of 2019 and first days of 2020 saw particularly hazardous fire weather, with further significant fires igniting while existing fires experienced renewed flares, as heatwave conditions continued into early January. Extreme heat again affected southeastern Australia at the end of January and the start of February. See Special Climate Statement Extreme heat and fire weather in December 2019 and January 2020.
The first four months of the year were warmer than average for large parts of Australia, particularly across the north, while the southeast experienced cooler than average mean maximum temperatures in February to April. Above average rainfall and increased cloud cover over the southeast during this period suppressed maximum temperatures. With most of Australia's major climate drivers neutral during late summer and autumn, it is likely that a north–south temperature gradient in the Indian Ocean, with surface waters in the tropics much warmer than average, contributed to the higher number of northwest cloudbands that affected Australia.
It was the coolest May since 2011, and the first month since October 2016 where Australia's national mean temperature was below average for the month. Both mean maximum and mean minimum temperatures were cooler than average for the month over much of Australia.
It is common for mean maximum temperatures to be very much warmer than average over most of Australia during periods of low rainfall during the cooler months of the year, while mean minimum temperatures are cooler than average in the inland southeast. Clear skies and sunny days are typical of central and inland eastern Australia during the cool season in dry years. Reduced cloud cover, low humidity, and low soil moisture leads to a large diurnal temperature range (the difference between daily maximum and minimum temperatures), with both higher daytime temperatures and cooler nights. Minimum temperatures during the winter months were below average over much of southeastern Australia during winter while mean maximum temperatures were above or well above average over most of Australia.
Extreme heat affected northern Australia and the Top End of the Northern Territory during August. There was significant early-season heat in northern Western Australia late in the month with some stations breaking their previous August record multiples times.
The heat across northern Australia continued into spring, with September mean maximum temperatures warmest on record for much of the northwest of Australia, and further early-season records set in the northwest during the first half of the month. September was a warm month for all of Australia, with both mean maximum and mean minimum temperatures very much warmer than average over much of the continent. For Australia as a whole it was the second-warmest September on record.
While October was also warmer than average, mean maximum temperatures were close to average or cooler than average for most inland regions, southern Victoria, and Tasmania, and mean minimum temperatures were close to average for Central Australia.
November was extraordinarily warm, with both the national mean maximum and mean minimum temperature the warmest on record for November for Australia as a whole. Mean minimum and mean maximum temperatures were very much warmer than average to highest on record over most of Australia, except the west and southwest of Western Australia. Significant heatwaves affected parts of Australia several times during the month, including much of northwest to southeast Queensland around the middle of the month, and much of southeast and eastern Australia towards the end of the month. The extreme heat continued into the first days of December.
Spring as a whole was also the warmest on record for Australia in terms of national mean temperature. Mean minimum temperatures were particularly warm, coming in 0.45 °C above the previous record in spring 1998.
December saw cooler than average temperatures over large areas of the northwest and Central Australia as tropical lows during the middle third of the month brought heavy rain and cooler temperatures stretching from the Pilbara and Kimberley into South Australia.
|Maximum Temperature||Minimum Temperature||Mean Temperature|
|New South Wales||86||+0.76||104||+1.06||97||+0.91|
|Tasmania||= 69||+0.06||= 88||+0.33||83||+0.20|
Annual rainfall close to average; some recovery from drought in the southern Murray–Darling Basin
Rainfall for the year was close to average overall for Australia; below average in parts of the west and southeast Queensland, but above average in parts of the northwest and the southeast.
The national total rainfall for 2020 was 4% above the 1961–1990 average at 483.4 mm (the 1961–1990 average is 466.0 mm).
Rainfall for the year was below average for parts of southeastern and east coast Queensland, the west and southwest of Western Australia, and western Tasmania. Annual rainfall totals were in the lowest 10% of historical observations for small parts of west coast Western Australia.
Annual rainfall was above average for large parts of New South Wales and parts of South Australia between the Flinders Ranges and Lake Eyre / Kati Thanda, and also for much of northern and eastern Western Australia, and large parts of the Northern Territory away from the Top End and the far south. Above average rainfall in the Kimberley was largely a result of tropical systems during December, whereas in New South Wales the contributions was spread more across the year, mostly during February to April and August to October, as well as from a wet December.
February rainfall was above average for most of the western half of Western Australia, and along the track of tropical cyclone Esther across the base of the Top End and the northern half of the Kimberley.
Rainfall was above average for large parts of eastern Australia during February to April.
Widespread heavy rainfall during the first half of February across much of Queensland and along the east coast of Australia contributed to both riverine and flash flooding in some areas of New South Wales and Queensland. Renewed heavy rainfall at the end February and in early March, partly associated with the remnants of tropical cyclone Esther, led to further widespread flooding in Queensland and heavy rainfall as far south as Victoria.
Rainfall during February assisted in the management of bushfires which had been burning in some areas of eastern Australia since late 2019. All fires in New South Wales, Victoria, and Tasmania were contained by the end of February.
April rainfall was above average for much of southeastern Australia, leading to significant inflows into many southern Murray–Darling Basin water storages.
The middle of the year was notably drier, with May–July rainfall in particular below or well below average across much of the southern half of Australia. For the southern Australian region (south of 26°S) May–July rainfall was the seventh-lowest on record compared to all May–July periods since 1900. For Australia as a whole June rainfall was the third-lowest on record.
However, during July several low pressure systems off the east coast of Australia and a complex low before mid-month brought periods of very heavy rain to the east coast, and above average rainfall for the month in eastern Victoria and coastal New South Wales.
As the Pacific Ocean began to lean towards La Niña in late winter conditions again turned wetter, with above average rainfall over large areas during August, September, and October. While not lasting long enough to be considered a negative Indian Ocean Dipole event, surface temperature patterns in the Indian Ocean reflected a "negative Indian Ocean Dipole-like" state during late winter to early spring, which also favoured above average rainfall over eastern and southern Australia.
During November the La Niña weakened temporarily. Rainfall for the month was above average for much of the north, west, and southwest of Western Australia, but below or very much below average for much of the eastern two thirds of Australia. A large number of cold fronts brought rain to the South West Land Division during November in what had otherwise been a sequence of generally below average rainfall months for that part of Western Australia since April.
December rainfall was above or very much above average for much of the country, and highest on record for the northern coast of New South Wales. A slow-moving low pressure system and coastal trough resulted in very heavy rainfall and flooding for parts of northeastern New South Wales and southeastern Queensland during the middle of December. Tropical lows affected the west of the country around mid-December, bringing torrential rain there too. For the country as a whole, it was the fourth-wettest December on record.
Rainfall deficiencies and water storages
Following Australia's driest year on record in 2019, at the start of 2020 there were significant multi-year rainfall deficiencies across much of Australia. Rainfall anomalies were very large at longer timescales; below average rainfall over most months over much of the country between early 2017 and the end of 2019 had allowed very large deficiencies to accumulate (see Special Climate Statement Drought conditions in eastern Australia and impact on water resources in the Murray–Darling Basin). The impact of low rainfall over the period was exacerbated by well above average temperatures, which in turn drive higher rates of evaporation where water is available.
While short-term rainfall deficiencies for periods less than one year in length diminished across the first half of the year, and were largely removed by late winter, the multi-year deficiencies persisted with much less significant change. Additionally, large areas of Western Australia saw very little rain during April to July, and short-term rainfall deficiencies emerged across much of southwest Western Australia starting from April. This was in addition to the existing multi-year rainfall deficiencies in the region for the period commencing in early 2018.
In the east of the country, generally wetter conditions from January to April saw many water storages start to recover. While those in the southern Murray–Darling Basin saw significant increases during 2020, those in the northern Basin fared less well, and storage levels remained low at the end of the year.
Water storage in the northern Basin had reached a record low of 5.4% of combined capacity in mid-January 2020, 7.5% lower than at any point during the Millennium Drought, and did not reach above 26% during the year before dry conditions and downriver releases saw levels decline in late spring. Storages in the northern Basin remained below 25% capacity at the end of December.
In the southern Basin, the total water storage was 41.2% at the beginning of 2020. This further declined to 36.8% in March. Total storage volume in the southern Murray–Darling Basin typically decreases until late April as this is the period when the bulk of downriver releases occur, and inflows are on average lower. From mid-autumn storages in the southern Basin experienced steady increases throughout the year, and were at 68.8% at the end of November.
Outside of the Murray–Darling Basin and the southeastern States water storages experienced a more limited recovery during the year, and in the north and the west of the country water storage levels continued to fall in 2020.
Many of the storages in northern Australia rely on the regular wet season rainfall to replenish water levels following the drawdown on stored water over the dry season. However, rainfall for the northern wet season was lower than average in both 2018–19 and 2019–20.
By the end of 2020, Darwin's water storages and Wivenhoe in southeast Queensland had dropped to their lowest levels in 10 years, and Lake Argyle in the eastern Kimberley had dropped to its lowest level in almost 30 years.
Eight tropical cyclones were recorded in the broader Australian region during the 2019–20 tropical cyclone season, below the long-term average of eleven (for all years since 1969–70). Three tropical cyclones reached severe (category 3).
Three tropical cyclones crossed the coast (Blake, Damien, and Esther). Severe tropical cyclone Damien crossed the coast near Karratha in Western Australia at category 3 strength. The Dampier weather radar sustained significant damage, and Karratha Airport recorded its highest wind gust in 17 years of wind observations (194 km/h on 8 February).
As of 31 December 2020, the 2020–21 tropical cyclone season was yet to see any tropical cyclones.
The tropical cyclone season typically runs from 1 November to 30 April, although tropical cyclones can and do form outside of those bounds (for instance, Mangga was active during May 2020). All tropical cyclones existing between 1 July and 30 June the following year count towards the season total. The broader Australian region covers the area south of the Equator and between 90°E and 160°E, and includes Australian, Papua New Guinea, and Indonesian areas of responsibility.
|New South Wales||104||636.7||+14%|
Major climate influences during 2020: mostly neutral, with La Niña from spring
In stark contrast to 2019, which was dominated by one of the strongest positive Indian Ocean Dipole (IOD) events in the historical record, the main drivers of natural climate variability in Australia were close to neutral for much of 2020.
The Southern Annular Mode (SAM) was positive for much of May and June. During winter, a positive SAM typically means less rainfall for southwest Western Australia, southern Victoria, and Tasmania as the rain-bearing westerly winds contract towards the south pole and fewer storm systems and cold fronts encounter Australia's southern coasts. Below average rainfall over the southern half of Australia around the middle of the year is a reflection of this pattern.
During July and August much of the north and east of the Indian Ocean basin, including waters to the northwest of Australia, were warmer than average. The IOD reached values indicative of a negative IOD for a number of weeks during late winter and early spring, but these values were not sustained long enough (a minimum of eight weeks) to be considered an IOD event. Negative IOD events in winter and spring favour above average rainfall across much of eastern and southern Australia, and it is likely sea surface temperature patterns in the Indian Ocean contributed to above average rainfall over Australia between August and October.
The most significant natural climate driver during 2020 however was La Niña. The Pacific Ocean began cooling over autumn, with early indicators of a developing La Niña emerging from around June. The event matured over winter and was declared in September.
The Southern Annular Mode was positive during early November and much of December. La Niña tends to favour positive SAM and during 2020 the polar vortex over Antarctica was the strongest on record during spring, further strengthening the push towards positive SAM. SAM during spring typically enhances the wet signal of La Niña in parts of eastern Australia, although western Tasmania is typically drier as the westerly winds which bring cold fronts and storms are suppressed.
In November trade winds in the Pacific Ocean weakened, temporarily weakening the La Niña; the SAM also weakened; and the Madden‐Julian Oscillation was active over the Atlantic and Indian Oceans rather than near Australia—all three factors which reduced the push towards above average rainfall over Australia. November was the warmest on record for Australia and rainfall was well below average; such temperatures are unusual for La Niña.
The strength of the La Niña increased again by the end of the November, and reached moderate to strong levels in December. La Niña conditions remained weaker than at the same time of year during the 2010–11 event throughout 2020.
In addition to the influence of natural drivers, Australia's climate is increasingly affected by global warming and natural variability takes place on top of this background trend. Australia's climate has warmed on average by 1.44 ± 0.24 °C since national records began in 1910, with most of the warming occurring since 1950. The ocean waters around Australia have also warmed significantly over the past century, and have been very warm consistently across the past two decades. The background warming trend can only be explained by human influence on the global climate. The role of climate change is further discussed in State of the Climate 2020.
There has been a significant decline in April to October rainfall observed over southeast and southwest Australia including in higher rainfall parts of the Murray–Darling Basin in recent decades. In the southeast of Australia April–October rainfall has declined by around 12% since the late 1990s. There has been a decline of around 16% in April–October rainfall over the southwest of Australia. The drying trend is particularly strong for May–July across southwest Western Australia; this region has seen May–July rainfall decrease by around 20% since 1970.
Conversely to the drying trend in the south, there has been an observed increase in rainfall across most of northern Australia since the 1970s.
Concentrations of all the major long-lived greenhouse gases in the atmosphere continued to rise in 2020 despite a temporary slow-down in global fossil fuel emissions of carbon dioxide (CO2) during early 2020 associated with the COVID–19 pandemic.
The atmospheric CO2 level, measured at Cape Grim, Tasmania, was 410.6 parts per million (ppm) by the end of 2020, an increase of 2.1 ppm for the year. This marks a 47% increase from the pre-industrial concentration of 278 ppm in 1750.
See State of the Climate 2020 for further information.
Sea surface temperatures equal-fourth-warmest on record for the Australian region as a whole
The annual 2020 sea surface temperature (SST) anomaly for the Australian region was the equal-fourth-highest on record; 0.59 °C above the 1961–1990 average based on data from the NOAA Extended Reconstructed Sea Surface Temperature dataset, ERSST v5. SSTs around Australia have warmed by around one degree since 1910, similar to the increase in temperature observed over land. Above average annual SSTs have been observed for the Australian region for every year since 1995, and have been persistently high for the past decade.
Sea surface temperatures were very much warmer than average (i.e. in the highest 10% of historical observations) across waters around the northern half of Australia and across the northern half of the Tasman Sea. Waters were also warmer than average for most areas around the southern half of Australia, but close to average in a region south of Tasmania and the the southwest of Western Australia. Farther away from Australia, SSTs were warmest on record in an area to the east of Papua New Guinea covering the Bismarck and Solomon seas and extending towards Fiji, and also warmest on record in parts of the Southern Ocean adjacent to eastern Antarctica. SSTs were above average to highest on record for large areas of the western Pacific Ocean and central regions of the Indian Ocean.
SSTs remained warm throughout the year, with large areas in the highest 10% of historical observations in each month. For the northern tropics region every month during 2020 except December was amongst the five warmest on record, and each month from January to April was the second-warmest on record for their respective month. For the Great Barrier Reef region, monthly averaged SSTs were the warmest on record for February and second-warmest on record for March. Accumulated heat in waters east of Queensland led to a mass coral bleaching event, with very widespread bleaching detected across the Great Barrier Reef.
Mean SSTs for the year were the second-warmest on record for the Northern Australian region and equal-second-warmest for the Coral Sea region, (+0.76 °C for the Northern Australian region, behind +0.96 °C in 2016, and +0.73 °C for the Coral Sea, tied with 2017 and behind +0.83 °C in 2016).
Waters were warmer than average in parts of the Maritime Continent, and in the north and east of the Indian Ocean during July and August, as the Indian Ocean approached, but did not sustain, a negative Indian Ocean Dipole (IOD) like state.
The first signs of the developing La Niña were also seen from mid-winter as small areas of cooler than average SSTs were seen in the eastern Pacific Ocean, with cool anomalies stretching across much of the central and eastern equatorial Pacific in September when the event was officially declared. SSTs were up to two degrees cooler than average in some areas of the eastern equatorial Pacific in September and in the central equatorial Pacific from October to December.
For the globe as a whole, the average annual sea surface temperature for 2020 was 0.60 °C above the 1961–1990 average, the third-warmest on record in the ERSST v5 dataset which commences in 1854. The warmest and second-warmest years on record are 2019 and 2016 (+0.64 °C and +0.63 °C respectively), and eight of the last ten years have been amongst the ten warmest on record.
Please note this list is not exhaustive—for a more complete summary of individual events, including those affecting smaller geographical regions or causing limited damage, please consult the Monthly Weather Review.
Continuing a very warm period in the last days of 2019, the first days of 2020 saw extremely high temperatures across parts of southeastern Australia in northerly winds driven by a cold front and trough (see Special Climate Statement 73 – Extreme head and fire weather in December 2019 and January 2020).
Ahead of the front many stations in New South Wales observed their warmest January day on record on the 4th or 5th. Penrith reported a maximum temperature of 48.9 °C on the 4th, the highest temperature reported in a metropolitan area since reliable records began. Meanwhile behind the cold front and trough some stations in South Australia and Victoria set records for their coolest January day on record, and some in Western Australia observed record low daily minimum temperatures for January.
Fires in eastern Australia, which significantly increased in activity over the New Year period, produced widespread thick smoke with poor air quality affecting large areas for a number of days, particularly during the first half of the month. A number of cities, including Melbourne, Canberra, and Sydney, were affected. On 14 January, Victoria had the worst air quality in the world as smoke from the East Gippsland fires spread. Widespread rainfall on 20 and 22 January helped reduce the number of uncontained bushfires. Following further rainfall around mid-February, all fires in New South Wales, Victoria, and Tasmania were declared contained by the end of February.
Following some severe storms in southeast Australia around mid-January, more widespread and very damaging storms affected the region on the 19th and 20th.
Showers and thunderstorms developed across central and eastern Victoria during the afternoon of the 19th and extended across the southwest in the evening. Heavy rainfall, giant hail, and damaging winds were observed with a number of storms. Hail up to 5.5 cm in diameter was observed in Glen Iris, and between 3 and 5 cm in a band across the eastern and inner southeastern suburbs of Melbourne. More than 1360 requests for assistance were made in the Melbourne region, and more than 3000 insurance claims lodged.
One of the most severe hailstorms recorded in the ACT occurred on 20 January. Hail of 4 to 6 cm in diameter fell across a region extending from the southern half of Belconnen through Acton to the inner southern suburbs. Extensive damage was reported to buildings and motor vehicles. More than 1900 calls for help were made to emergency services and more than 15 000 insurance claims were lodged.
Storms also affected the Sydney region, with more than 4000 insurance claims arising from strong winds, lightning, and hail in the Sutherland Shire and northern beaches.
Estimates of insured losses across Canberra, Melbourne, and Sydney had reached $320m in damage shortly after the event.
An intense dust storm swept through a very large area of South Australia, New South Wales, and Victoria during 23 and 24 January. Visibility was severely reduced with many locations reporting less than 200 m.
A very hot air mass brought a period of very high temperatures across southern Australia during the last days of January. At times temperatures were close to or exceeded 40 °C over wide regions, including coastal areas. Many records were set in Victoria, New South Wales, and Tasmania; mostly on the 31st. At the same time, humidity was very high as tropical moisture drifted south, with record-high dewpoint temperatures making for exceptionally muggy and unpleasant conditions.
In Victoria, high temperatures were accompanied by severe thunderstorms in the early evening of 31 January, downing trees, damaging homes and powerlines, and causing traffic hazards. Several electricity transmission towers were knocked to the ground near Colac, with Mt Gellibrand reporting a maximum wind gust of 120 km/h. Strong northerly winds had carried dust from northwest Victoria to southern parts of the State, which resulted in 'mud rain' when the storms came through.
There was widespread heavy rainfall across northern Australia from late January into the first eight days of February, including parts of inland southern Queensland, and over coastal New South Wales and southeast Queensland during the second week of the month.
In Sydney the runoff from this event was enough to almost double the amount of accessible water in Sydney's urban supply system storages. Warragamba, the largest storage in the system, went from 42% of capacity on 8 February to 81% on 18 February, an increase of 800 GL, almost enough water to fill the Sydney Harbour twice over. Thirty five percent of the catchment was burnt by bushfires during 2019–20. The speed and volume of runoff was likely to have increased due to the lack of vegetation.
Heavy rainfall returned to southern Queensland in the second half of February, including severe thunderstorms over the southeast coast on 12 February, with swift water rescues, inundation of homes, and a number of roads cut or closed.
Flash flooding and riverine flooding affected parts of southeast and inland Queensland and inland and coastal areas of New South Wales, extending into the second half of the month. Significant flood levels were recorded in numerous Queensland catchments, most notably in the Georgina/Eyre, Logan/Albert, Condamine/Balonne, and Warrego catchments. In eastern New South Wales major flooding occurred on the Orara, Hawkesbury/Nepean, and Georges rivers. Local flooding resulted in various parts of Greater Sydney, and there was coastal erosion on multiple beaches.
A tropical low tracked west across the Kimberley in Western Australia during the first week of February, before developing into tropical cyclone Damien on the 6th while northwest of Broome. Damien intensified to a severe system (category 3) before making landfall over the Karratha and Dampier region in the afternoon of the 8th. The Dampier weather radar sustained significant damage, and Karratha Airport recorded a 194 km/h wind gust on the 8th—its highest gust in 17 years of wind observations.
A persistent trough near the west coast of Western Australia combined with an upper level cut-off low pressure system, generating thunderstorms over the South West Land Division during the last week of February. The State Emergency Service responded to more than 600 requests for assistance with wind damage, downed trees, and water ingress in the Central West, Lower West, and South West districts. In Perth it was the most severe storm since the hailstorm on 22 March 2010.
Tropical cyclone Esther made landfall close to the Northern Territory and Queensland border on 24 February. The system weakened to an ex-tropical cyclone while travelling over the Barkly District in the Northern Territory, then moved slowly west. The remnant low persisted into early March, producing widespread moderate to locally heavy falls over the southern Top End and Kimberley, before tracking eastwards across the Northern Territory again then moving into western and then southern inland Queensland.
Western Queensland experienced renewed heavy rain and flooding in the Georgina, Diamantina, Bulloo, Paroo, and Warrego rivers and the Cooper Creek catchment. Some properties were isolated for a number of weeks, and several roads were closed across the region, disrupting major transport routes.
Major flooding also occurred in the lower Balonne River in early March, resulting from heavy rainfall over the Balonne and Maranoa rivers during February.
Flooding during March occurred on already elevated river levels in tributaries of the Lake Eyre and Murray–Darling basins.
Moisture from the remnants of ex-tropical cyclone Esther fed into a slow-moving trough over inland New South Wales, generating widespread rain and occasional intense thunderstorms over southeastern Australia. In Victoria the State Emergency Services received more than 300 calls for assistance on 5 March, mostly related to flooding and building damage, while flash flooding caused disruptions to transport.
Accumulation of heat in ocean waters east of Queensland during February and into March led to coral bleaching across the Great Barrier Reef. This is the third mass bleaching event to affect the reef in five years.
A strong cold front which crossed Victoria on 3 April brought a sharp decrease in temperatures and considerable rainfall to parts of Victoria and the southeast between the evening of the 3rd and 5th. Heavy rain and strong winds resulted in flooded roads, fallen trees, and damage to buildings; the State Emergency Service responded to more than 400 calls for help.
Strong squally winds followed the passage of another cold front on 11 April, with gusts of 131 km/h reported at Wilsons Promontory Lighthouse; the State Emergency Service received more than 450 calls, mostly for fallen trees.
Severe thunderstorms affected the Capricornia and Central Highlands districts of Queensland on 19 April, with giant hail, up to 8 cm in diameter, reported around Rockhampton and Yeppoon. Hail that size is rare in April in central Queensland.
Ex-tropical cyclone Mangga combined with an upper level trough and strong cold front while approaching Western Australia on 24 May. Widespread severe weather resulted over much of the west of Western Australia between the 24th and 26th, including strong and gusty winds, abnormally high tides and storm surges. Peak wave heights in excess of 8 m were reported in the southwest, with significant beach erosion and coastal inundation at multiple locations including the Perth Metro area, Mandurah, Albany, Dunsborough, Port Geographe, Kalbarri, Geraldton, and Carnarvon.
Strong winds through the Central West district whipped up large amounts of dust, blanketing many towns and reducing visibility below 500 m in Geraldton. Western Power reported at least 62 000 homes without power, affecting communities all across the west of the State.
A strong cold front brought a band of thunderstorms, accompanied by lightning and winds in excess of 100 km/h to southern central Victoria in the early hours of 20 May. The hardest hit areas were to the west of Geelong. More than 100 houses were severely damaged, as thunderstorms produced a tornado with winds estimated to be in excess of 150 km/h. The State Emergency Service received around 130 calls for help from the Geelong area, and 220 across the State.
Two low pressure systems in the Tasman Sea brought heavy rain, isolated flash flooding, and high seas to coastal New South Wales during July.
A cold front and complex low pressure system crossed southeast Australia from 11 July, with the low deepening over the Tasman Sea during the 13th and 14th before moving away to the east during the 15th. Heavy rainfall over the South Coast district resulted in local flooding while a powerful sea swell, with wave heights of 5 to 6 m, led to significant coastal erosion and hazardous beach conditions. Powerful waves persisted for several days, with peak waves exceeding 11.5 m recorded by the wave rider buoy offshore of Sydney.
Another low pressure system developed off the coast of southeast Queensland in late July, with the deepening low moving south along the New South Wales coast from the 26th to 28th. Heavy rain fell over coastal New South Wales and much of Gippsland, resulting in localised flooding in several areas, including Newcastle, the Lower Hunter, and the South Coast District. Some areas also experienced coastal erosion.
Heat built in northwestern Australia over August, with records set at a large number of stations in Western Australia during the last week of the month. West Roebuck, just east of Broome, reached 41.2 °C, a national record for August, on the 23rd, a day after Yampi Sound (75 km northeast of Derby) reached 40.7 °C on the 22nd. Along with 40.1 °C at West Roebuck on the 27th, Australia had observed three 40 °C days in August within a week. There is only one other instance of a 40 °C day during August in the observational record; 40.0 °C at Kulumburu Mission on 27 August 1970.
Port Hedland Airport exceeded its previous August record (36.8 °C) on 7 out of 90 days between the 23rd and 31st; Marble Bar exceeded its previous August record (38 °C) on 6 consecutive days between the 24th and 29th; and Telfer Aero exceeded its previous August record (36.2 °C) on 6 consecutive days between the 24th and 29th.
A complex low pressure system and cold front crossing southern Australia brought heavy rainfall and a significant cold outbreak to the southeast of the country during the first week of August.
Widespread heavy snow fell on the 4th in the Alpine region, and settled down to lower levels, including at Mount Macedon, the Otway Ranges, Dandenong Ranges, Wallan and Sunbury in Victoria. In Tasmania snow closed the Huon Highway south of Hobart, and a few centimetres fell in Launceston; snow settling on the ground in Launceston is very rare. Liawenee set a record for the lowest temperature observed in Tasmania with −14.2 °C on the 7th.
A cold front brought cold, wet and windy conditions to Victoria and southern New South Wales between 21 and 23 August, with some alpine areas receiving more than 50 cm of snow. Up to 30 cm of snow fell around Orange in New South Wales, with light falls in the Blue Mountains. Snow was also reported in Victoria's Grampians, Dandenong Ranges, Ballarat, and Mount Macedon, while flurries were reported at Beaumaris on the coast in Melbourne's southeast. Snow fell in many Canberra suburbs and settled widely above 750 m, with snowfalls continuing in the Brindabella Ranges over the following days.
A cold front and associated trough crossed Victoria during 27 August, resulting in squally westerly winds across southern and mountain districts; Wilsons Promontory Lighthouse reported a wind gust of 157 km/h (85 kts). The State Emergency Services received more than 1000 calls for help, mostly for downed trees and powerlines.
Several cold fronts associated with a complex area of low pressure brought widespread showers, isolated thunderstorms, small hail and gusty winds to southeast Australia between 21 and 26 September. Widespread snow was reported about the ranges in South Australia and some snow was reported in lower ranges in New South Wales, including at Orange, Oberon, the Barrington Tops, and the Brindabellas. In Victoria snow blanketed parts of the southwest and central highlands, and fell to lower levels in some areas, including at Mount Macedon, the Otway Ranges, Ballarat, Lismore, Ararat, and Mortlake.
Damaging winds were observed through parts of the Illawarra, Central Tablelands, Southern Tablelands and Sydney Metropolitan areas in New South Wales.
Widespread thunderstorms affected central and southeast Queensland during the last week of October, bringing heavy rainfall to some locations, flash flooding, and strong wind gusts. On the 28th there were reports of large hail up to 6 cm in diameter south of Gayndah, fallen power lines in the Caboolture area, and localised flash flooding. On the 31st giant hail up to 14 cm in diameter was reported along a path through the southern outskirts of Brisbane from Amberley to the northern suburbs of Logan, giant hail up to 7 cm around Gatton and Gympie. There was wind damage from Redcliffe to Kingston with gusts over 100 km/h observed around Moreton Bay.
Heatwaves affected parts of Australia several times during November. A low- to severe-intensity heatwave affected much of northwest to southeast Queensland around the middle of the month. A more significant heatwave came at the end of the month when very warm air was directed from the middle of the continent into southeastern and eastern Australia as frontal systems combined with a heat trough over inland Australia.
Large areas experienced daily maximum temperatures more than 10 degrees above average over a number of days. On the 29th many stations in New South Wales had their warmest November night on record, and Delta, west of Bourke, reported a minimum temperature of 33.8 °C, the highest November minimum temperature ever recorded in New South Wales, and the fourth-highest for all of Australia.
A tornado occurred at Horsham in Victoria, damaging roofs and trees along a narrow path on 7 December as a line of showers associated with a cold front passed through around 1 am. Post event assessment indicated the tornado was most likely EF1 strength. Cool season tornados are typically observed once or twice a year, but it is rare that they move through populated areas—many may go unnoticed in sparsely populated areas.
A slow-moving low pressure system and trough near the southern Queensland coast brought widespread heavy rainfall, damaging winds, abnormally high tides and dangerous surf to the northern half of the New South Wales coast and southeast Queensland from 12 to 17 December. Widespread three-day totals in excess of 300 mm were observed in areas of the Gold Coast Hinterland and New South Wales' Northern Rivers and Mid North Coast districts, with the highest being 918.0 mm at Upper Springbrook Alert over 13 to 15 December (including 475.0 mm in the 24 hours to 9 am on 13 December).
The New South Wales State Emergency Service received more than 1000 calls for help and the Queensland Fire and Emergency Services received more than 1500 calls for help. Flash and riverine flooding occurred in Gold Coast hinterland in southeast Queensland, and in the Tweed, Clarence, Richmond/Wilsons and Bellinger rivers in New South Wales. Strong winds were observed, including gusts in excess of 100 km/h at exposed coastal locations like Byron Bay.
Damaging storm surges coincided with king tides, resulting in hazardous surf conditions and major coastal erosion at numerous beaches in northeast New South Wales and southeast Queensland. Buoys offshore of southeast Queensland observed waves reaching up to 10 m in height, and an 11 m maximum wave height at the Brisbane Buoy, with waves reaching up to 5 m inshore.
All values in this statement were compiled from data available on the issue date. Subsequent quality control and the availability of additional data may result in minor changes to final values.
Accessing Australia's climate change datasets
The Bureau collects, manages and safeguards Australia's climate data archive. Several datasets have been developed from this archive to identify, monitor and attribute changes in the Australian climate. You can access these datasets on our website.
This statement has been prepared using the homogenised Australian temperature dataset (ACORN-SAT) for area-averaged temperature values and the observational datasets. Mapped analysis uses AWAP temperature data and AWAP rainfall data up to 2019. From 2020 area-averaged rainfall values and mapped analyses use the new AGCD dataset.
A note on base periods
In climatology a baseline, or long-term average, is required against which to compare changes in climate over time. Use of the 1961–1990 base period for reporting anomalies follows international conventions set by the World Meteorological Organization.
A period of minimum 30 years is required to form a robust climatological average, accounting for decadal variability. In general, baseline climatological periods try to make use of the period with the best data coverage. The 1961–1990 period is used globally as it coincides with consistent national temperature records observations and allows comparison across countries. However alternate averaging periods are also used for other purposes, such as facilitating comparison to a more recent period for climate outlooks, or to the pre-industrial period for long-term climate change.
Product code: IDCKGC5AR0