Seventh-wettest financial year on record with close to average temperatures

The 2022–2023 financial year (1 July 2022 to 30 June 2023) had close to average temperature and above average rainfall, and was marked by periods of flooding in large parts of Australia.

Temperature

  • Australia's national mean temperature for the financial year was 0.13 °C warmer than the 1961–1990 average.
  • The national mean maximum and mean minimum temperatures were 0.10 °C and 0.16 °C above average respectively.
  • The maximum temperature was above average for parts of northern Australia and almost all of Tasmania and below average in areas of every mainland state.
  • The minimum temperature was above average for parts of northern Australia and south-east and central Australia and below average in parts of Western Australia, Northern Territory and New South Wales.

Rainfall and water resources

  • For Australia overall rainfall was 32% above the 1961–1990 average at 612.6 mm, making this financial year the 7-th wettest on record (since 1900) and the wettest since 2010–2011.
  • Rainfall was above average for much of Australia with highest on record rainfall for parts of northern Queensland.
  • Rainfall was below average for parts of south-eastern Queensland, north-eastern New South Wales, south-western Tasmania and for scattered areas in the west of Western Australia.
  • Australia's second-wettest October and spring on record led to extensive riverine flooding in the New South Wales and Victorian areas of the Murray–Darling Basin, and then into South Australia. Significant flooding also affected northern Tasmania, southern Victoria and southern Queensland.
  • Significant flooding affected the Kimberley in Western Australia at the end of December and in January due to prolonged heavy rainfall from ex-Tropical Cyclone Ellie.
  • Extreme multi-day rainfall in late March and early April resulted in floods in north-eastern Northern Territory and north-western Queensland.
  • Widespread above average rainfall conditions contributed to above average streamflows across much of Australia, with highest on record observed across Victoria and inland New South Wales, while most of Western Australia recorded below average streamflow.
  • Surface water storage levels across the country remained high in large water storages, but levels decreased in some small storages especially in south-east Queensland. Some large storages reached full capacity for the first time in many years, including Dartmouth, Thomson, Lake Eildon and Lake Argyle, the largest water supply storage in Australia.
  • Groundwater storage levels varied considerably across Australia. In areas of high rainfall and flooding, such as Victoria and inland New South Wales, groundwater levels increased, with above average levels for many bores. This contrasted with below average groundwater levels in the Northern Territory and along the Victoria–South Australia border.

Tropical cyclones

  • There were 7 tropical cyclones in the Australia region, less than the average 11 across all financial years since 1969–1970, and also less than the average of 9 since 2000–2001.
  • Only 2 tropical cyclones with at least Category 1 strength (Ellie and Ilsa) made landfall on the Australian mainland, fewer than the long-term average of 4 (since 1969–1970).

Climate influences

  • Sea surface temperature for the Australian region was the third highest on record at 0.64 °C above the 1961–1990 average.
  • La Niña became established in September, peaked in November, before easing in early 2023.
  • The negative Indian Ocean Dipole event was very strong from July through to September, before weakening and dissipating in November.
  • The Southern Annular Mode was mostly positive from mid-August to February.

A warmer than average 12 months

Nationally-averaged, the mean temperature for Australia for the 2022–2023 financial year was 0.13 °C above the 1961–1990 average.

Both daytime and night-time temperatures were warmer than average. The mean maximum temperature was 0.10 °C warmer than average and the mean minimum temperature was 0.16 °C warmer than average.

Maximum temperatures for the 2022–2023 financial year were above to very much above average in parts of the far northern tropics and above average for most of Tasmania. Maximum temperatures were below average for an area extending from the west coast of Western Australia into the central region of Queensland and for parts of inland New South Wales across into north-east and western Victoria and south-eastern South Australia.

Minimum temperatures for the 2022–2023 financial year were above to very much average for parts of the northern tropics, and above average in an area from the interior and south-east of Western Australia into eastern and northern South Australia and across into the western Queensland, and across south-eastern Australia. Minimum temperatures were below average from the west coast of Western Australia extending into the interior of Northern Territory and parts of inland and coastal New South Wales.

The national mean temperature for most months was close to or warmer than average for 2022-2023. However, cold outbreaks brought unusually low temperatures throughout late spring and into early summer. The November mean maximum temperature was the eight-lowest on record (compared to all Novembers since 1910). Wet conditions during November also brought cooler than average temperatures for most of Australia except for the far northern tropics.

The mean temperature for March was amongst the equal-tenth warmest on record, as heatwave conditions affected many areas of Australia. Maximum temperatures across the interior and the east coast of Australia were within the highest 10% since records began.

In May, the national mean temperature was the lowest since 2011 and the minimum temperature was the seventh-lowest on record and the lowest since 1944. Clear skies and light winds combined with cold fronts resulted in low daily minimum temperatures in large parts of the country.

June was among the seventh-warmest on record, and the national maximum temperature was among the tenth-warmest on record. Clear skies and light winds resulted in high daytime (maximum) temperatures in parts of northern and eastern Australia, with large parts of Queensland recording their highest mean maximum temperature on record (compared with all Junes since 1910).

Map of mean temperature deciles
Figure 1: Australian mean temperature deciles for the 2022–2023 financial year, relative to all years since 1910. See also maxima and minima.
Australian financial year mean temperature anomalies, compared to the historical average. The black line shows the 11-year moving average. The value for the 11-year average is positioned over the middle year of each 11-year block.
Maximum Temperature Minimum Temperature Mean Temperature
Rank
(of 113)
Anomaly
(°C)
Comment Rank
(of 113)
Anomaly
(°C)
Comment Rank
(of 113)
Anomaly
(°C)
Comment
Australia = 66 +0.10 78 +0.16 78 +0.13
Queensland 56 +0.17 = 92 +0.68 85 +0.43
New South Wales = 54 −0.01 = 66 +0.09 61 +0.05
Victoria 35 −0.31 94 +0.47 74 +0.09
Tasmania 94 +0.43 = 86 +0.24 91 +0.34
South Australia 72 +0.21 = 75 +0.24 74 +0.23
Western Australia = 77 +0.22 53 −0.16 67 +0.04
Northern Territory = 57 −0.15 = 59 −0.01 = 60 −0.07

The wettest financial year since 2010–2011

Nationally-averaged total rainfall for Australia for the 2022–2023 financial year was 32% above the 1961–1990 average at 612.6 mm, the seventh-wettest on record (compared to all financial years since 1900).

Rainfall for the financial year was above average for much of the country. Rainfall was very much above average (in the wettest 10% of historical observations) for much of northern and south-eastern mainland, and for east coast of Tasmania. It was highest on record for parts of northern Cape York Peninsula (Queensland) and smaller areas in the Tanami and Barkly (Northern Territory) and Kimberley (Western Australia) districts.

Rainfall was below average for parts of south-eastern Queensland, north-eastern New South Wales, south-western Tasmania and for scattered areas in the west of Western Australia.

For the Northern Territory as a whole, rainfall for the financial year was 50% above average, the seventh-highest on record. For Victoria and Queensland, statewide rainfall was the eighth-highest and nineth-highest on record respectively.

Spring 2022 was Australia's second-wettest on record, 112% above the 1961–90 national average for spring, with widespread and significant flooding across large areas of eastern Australia, particularly through inland New South Wales and parts of Victoria. Flooding during spring also affected Queensland, South Australia and Tasmania.

Record rainfall from the ex-Tropical Cyclone Ellie resulted in significant flooding in central and northern parts of the Northern Territory and parts of the Kimberley in Western Australia during the last part of December extending into January 2023.

Several days of locally heavy rainfall affected many areas of Queensland in the first week of January 2023 leading to major flooding along several rivers.

Storms and heavy rain across the northern tropics at the end of February and throughout the first ten days of March resulted in major flooding along the several rivers across eastern Northern Territory and north-western Queensland.

In contrast, May was an exceptionally dry month for Australia, the second-driest May on record, while June had large areas of below average rainfall in the east and west of the mainland.

Map of rainfall deciles
Australian rainfall deciles
for the 2022–2023 financial year, relative to all years since 1900.
Map of rainfall anomalies Map of rainfall totals
Australian rainfall anomalies for the 2022–2023 financial year, relative to all years since 1900 (left), and map of rainfall totals (right).
Financial year mean rainfall (mm) for Australia since 1900. The black line shows the 11-year moving average. The value for the 11-year average is positioned over the middle year of each 11-year block.
Monthly area-average total rainfall for Australia. The green bars are the total for the 2021-22 financial year, and the grey bars show the mean monthly total for the 1961-90 period. Select each month to view the value.
Rank
(of 123)
Average
(mm)
Departure
from mean
Comment
Australia 117 612.6 +32% 7th highest; highest since 2011
Queensland 115 825.8 +33% 9th highest; highest since 2011
New South Wales 106 662.8 +19%
Victoria 116 844.7 +27% 8th highest; highest since 2011
Tasmania 68 1370.0 +1%
South Australia 111 281.8 +26%
Western Australia 108 431.0 +26%
Northern Territory 117 817.8 +50% 7th highest; highest since 2011
Murray-Darling Basin 109 612.6 +24%

Water

Improved water availability influenced by wet soil and high inflows

In 2022–2023, the status of many of Australia's water resources was influenced by above average rainfall and wet soil conditions.

In response to very much above average rainfall, soil moisture in the root zone (soil moisture in the top 100 cm) was above to very much above average across most parts of northern Australia, New South Wales and Victoria. In contrast, soil moisture in south and western parts of Western Australia, and western Tasmania were below average.

Record heavy rainfall during August–November contributed to widespread flooding in inland New South Wales and Victorian parts of the Murray–Darling Basin, and then into South Australia. Significant flooding also affected northern Tasmania, southern Victoria, and southern Queensland. Significant flooding affected the Kimberley in Western Australia during December and January due to heavy rainfall from ex-Tropical Cyclone Ellie, and in north-eastern Northern Territory and north-western Queensland in late March and early April due to extreme multi-day rainfall and Tropical Cyclone Ilsa.

With widespread above average rainfall conditions, streamflows across much of Australia were above average, and highest on record streamflows were observed across Victoria and inland New South Wales, while most of Western Australia recorded below average streamflow.

Surface water storage levels for many parts of country remained high in large water storages, but levels decreased in some small water storages especially in south-east Queensland. In response to wet soil and high inflows, some large storages that had been below full capacity for many years reached to full capacity, including Dartmouth and Thomson Dam for the first time since November 1996, Lake Eildon for the first time since 2013 and Lake Argyle, the largest water supply storage in Australia, for first time since 2017. In contrast, a continued decline of inflows in areas with long-term rainfall deficiencies was reflected in low storages in some areas including south-west Western Australia.

Groundwater storage levels varied considerably across Australia in 2022–2023. In areas of high rainfall and flooding, such as Victoria and inland New South Wales, groundwater levels increased, with above average levels for many bores. This contrasted with below average groundwater levels in the Northern Territory and along the Victoria–South Australia border.

Above average soil moisture in most parts of the country

In 2022–2023, soil moisture in the root zone (soil moisture in the top 100 cm) was above to very much above average across most parts of northern Australia, New South Wales and Victoria, in response to very much above average rainfall. In contrast, soil moisture in south and western parts of Western Australia and in western Tasmania were below average.

At the beginning of the financial year, root-zone soil moisture was above average across much of Australia except the top end and south-west of Western Australia, largely due to wet conditions in the preceding 12 months. With the above average northern wet season (October to April) rainfall and record Australia's second-wettest spring rainfall in New South Wales and Victoria, soil moisture further increased across Northern Territory, Central Australia, and the south-eastern Australia. By December, soil moisture in most parts of Victoria, inland New South Wales, eastern Tasmania, and across the tropics were very much above average.

Soil moisture decreased over summer and autumn across the eastern mainland. At the end of the financial year, below to very much below average root zone soil moisture was recorded for most of Queensland, north-eastern New South Wales and eastern Tasmania. In the south-west of Western Australia, soil moisture continued to decline due to lower than average rainfall.

Root-zone soil moisture deciles map for  July 2022 to June 2023
Root-zone soil moisture deciles map from the Australian Water Resources Assessment Landscape model (AWRA-L) 7.0 for June 2022 (top left), December 2022 (top centre), June 2023 (top right), and July 2022 to June 2023 (bottom). Based on all years since 1911. About deciles.

Above average streamflows and major flooding across south-eastern and northern Australia

In 2022–2023, streamflows were very much above average (based on records since 1975) across much of Australia as a result of heavy rainfall and wet soil conditions, particularly in much of New South Wales, central and northern Victoria, far north and north-west of Queensland, and the Kimberly region of Western Australia. In contrast, streamflows in most part of south-west of Western Australia were below average.

Highest on record streamflows were observed at 17% of the 905 sites where streamflow is measured and where less than 20% of daily records were missing in the financial year. Higher than average streamflows were measured at 72% of sites, mostly in inland New South Wales and Victoria. Lower than average streamflows were measured at 5% sites, mostly in Western Australia and the east coast of Queensland. Streamflows were average at 22% of sites, mostly in parts of Western Australia, the Northern Territory, and Queensland.

Streamflow decile categoriesNo of sitesPercentage of sites (%)
Highest on record 156 17
Very much above average 228 25
Above average 271 30
Average 201 22
Below average 47 5
Very much below average 1 0
Lowest on record 1 0
Table of the number of streamflow sites in each decile category. Observations from 924 sites where streamflow is measured and which had at least 80% of daily observations available during the financial year.

Spring 2022 was Australia's second-wettest spring on record, and the wettest spring on record for New South Wales and for Victoria. In October, heavy rainfall lead to widespread flooding in the Murray–Darling Basin, both in New South Wales and Victoria, as well as in eastern Tasmania. From the beginning of October, Shepparton, Forbes, Echuca and many other towns in inland New South Wales and Victoria were severely impacted. By November, the Barwon River reached major flood level at Mungindi, as did the Darling River at Bourke, Tilpa, Wilcannia, and Walgett. By December, floodwaters had moved through the Menindee Lakes and reached South Australia, causing major flooding at Renmark, Loxton, Blanchtown, Overland Corner, and Murray Bridge, with multiple flood peaks observed at some locations. By mid-January, flood peaks reached the mouth of the Murray River.

In northern Australia, in late December and early January, ex-Tropical Cyclone Ellie brought flooding to northern areas of Western Australia, the Northern Territory and Queensland. Significant flooding of Western Australia's Fitzroy River occurred, causing substantial damage to transport infrastructure. In early March, significant flooding affected large parts of the eastern Northern Territory and north-western Queensland associated with a monsoon trough and a slow-moving tropical low. During mid-April, Severe Tropical Cyclone Ilsa brought high daily rainfall totals and flooding to parts of north-west Western Australia.

Streamflow deciles map for the 2022–2023 financial year
Streamflow deciles for the 2022–23 financial year, relative to all years since 1975.

Water availability

Water availability in urban centres

In urban centres, water availability is influenced by levels in surface water storages and groundwater, with augmentation through alternative sources — desalination or recycled water schemes — where storage volumes are not adequate.

Surface water storages that supply the major capital cities finished the financial year with volumes greater than 90% full, with the exceptions of those that supply Adelaide, Brisbane, and Perth. Rainfall was average to above average around most areas in 2022–2023 which helped to maintain high storage volume over the year.

Adelaide received above average rainfall, which resulted an increase in its storage volumes to 68.3% at the end of the financial year compared to 48.5% at the start. Adelaide's water supply needs are augmented by alternative sources, mostly water transfers from the River Murray, with some supply from desalinated water and groundwater.

Perth's surface water storages were 47.2% at the end of the financial year, which is similar to the start. Perth's water supply is more reliant on desalinated water and groundwater than surface water. The city's water supply strategy involves 'banking' of groundwater and desalinated water in its surface water storages during low demand periods to buffer peak supply period requirements.

Rainfall was below average around Brisbane, which resulted decrease in its storage volumes to 74.0% full at the end of the financial year, compared with 88.5% full at the start.

Percentage full of storage as of 30 June 2023 compared to same time last year (and back to 2010) for Australia's capital cities.

Surface water storages

High surface water volume in major water storages

Due to persistent rainfall during spring 2022, many major water storages in the Murray–Darling Basin filled quickly, with the total storages reaching 101.8% of accessible capacity by November. Collectively, major storages across Murray–Darling Basin ended the financial year with a total volume of 92.2%, a slight increase from the start (89.4%). Over the financial year, storages in the southern Basin increased from 88.0% to 92.1%. In contrast, storages in the northern Basin decreased from 96.2% to 92.7% due to dry conditions in May and June.

Rainfall and inflows from the Darling River continued to fill Menindee Lakes, which reached 120% of accessible capacity by the end of December and declined in 2023, ending the financial year with a total volume of 80.2%.

With wettest spring on record (since 1900) for New South Wales and Victoria, some large storages that had been below full capacity for many years, reached to full capacity and subsequently spilled. When Dartmouth Dam (3,785 GL accessible capacity) spilled in north-east Victoria, it was only the fifth such occurrence since the storage was completed in 1979, and the first since November 1996. The Thomson Dam (1,068 GL accessible capacity) in West Gippsland, which accounts for more than half of Melbourne's water supply, also spilled water for the first time since 1996. Lake Eildon, an important water storage for agriculture in northern Victoria, filled to its full accessible capacity (3,250 GL) for the first time since 2013.

Water levels in the storages of South East Queensland, which has been declining for about four years (except for a rapid rise in late 2021), continued to decrease during 2022–2023. Wivenhoe, the largest storage in South East Queensland, decreased from 90% to 71.4% full. However, the Nogoa Mackenzie rural system finished the financial year at 40.3% full, an increase of 17.7% from the start (22.3%).

Northern Australia received above to very much above average rainfall during the wet season (October–April), with Lake Argyle, the largest water supply storage in Australia, reaching over 100% in early February, the first time since 2017, and reached 121.4% of accessible capacity by March. Lake Argyle finished the financial year at 101% full, a significant increase from 69.7% at the start.

Map showing percentage full of storage systems at the end of 2022–2023
Percentage full of storages as of 30 June 2023.
Map showing percentage change in storage systems during 2022–2023
Percentage changes in storages over the financial year.
Percentage full of storage on 30 June 2023 compared to the same time last year (and back to 2010), for Murray–Darling Basin North, Murray–Darling Basin South, Menindee Lakes, Wivenhoe, Nogoa–Mackenzie and Argyle, systems.

Groundwater recovered to pre-drought condition in the east

Groundwater levels across Australia varied widely in 2022–2023, with 29% of bores below average, 27% average and 44% above average. High rainfall and flooding in some areas has continued to recharged stores that had been low due to prolonged drought conditions between 2017 and 2020. In contrast, groundwater levels have stable or decreased in other parts of Australia due to a lack of recovery from drought, or dry conditions in the financial year.

In the northern Murray–Darling Basin and south-eastern Queensland, groundwater levels continued to recover, following periods of heavy rainfall and flooding since 2021. Further high rainfall and flooding in 2022 affected the whole Murray–Darling Basin and returned groundwater levels to pre-drought conditions in many areas, including the aquifers of the Namoi and Condamine basins. In contrast, many of the bores in the Victoria–South Australia border region remain average to below average, reflecting both low rainfall in the recent years and long-term consequences of groundwater extraction.

In south-west Western Australia, groundwater levels have generally been in decline over the past 40 years due to decreasing rainfall and increasing groundwater demand. In efforts to restore groundwater levels, initiatives in recent years have included managed aquifer recharge and measures to reduce groundwater extraction. Average to above average winter rainfall in 2021 and 2022 resulted in recharge to surficial aquifers of the Gnangara Mound. This is an improvement from the previous two years of low winter rainfall resulting in low groundwater recharge and low groundwater levels. However, the groundwater level in more than 70% of bores in these regions remained average to below average.

In the top end of the Northern Territory, where groundwater recharge is reliant on wet season rainfall and streamflow, groundwater levels showed some improvement in the financial year after below average rainfall and groundwater levels earlier in 2022. Groundwater levels at majority (~90%) of bores were average to below average.

Map of groundwater levels
Australian Groundwater level status for the 2022–2023 financial year, based on data records since 1997, except for Tasmania where records start in 2008.
Groundawater level – Narrabri Groundawater level – Gunnedah Groundawater level – Main Range Volcanics Groundawater level – Dilwyn Formation Groundawater level – Gunnedah Groundawater level – Tindall
Groundwater levels in monitoring bores in the Narrabri and Gunnedah Formations in the Namoi catchment in the northern Murray–Darling Basin (top left and right), Main Range Volcanics in Upper Condamine, Queensland (middle left), Dilwyn Formation, South Australia-Victoria border (middle right), Gnangara Mound, Western Australia (bottom left), and Tindall aquifer in the Katherine region, Northern Territory (bottom right).

Australian region sea surface temperatures third-highest on record

2022–2023 sea surface temperature decile map
2022–2023 sea surface temperatures compared to historical records.
(From the NOAA Extended Reconstructed Sea Surface Temperature dataset, ERSST v5). About sea surface temperature regions and deciles.

The 2022–2023 sea surface temperature (SST) anomaly for the Australian region was the third highest on record, at 0.64 °C above the 1961–1990 average based on data from the NOAA Extended Reconstructed Sea Surface Temperature dataset, ERSST v5. Area-averaged SSTs were highest on record for each month between July and October, and within the highest 10% of historical observations (since 1900) for the remaining months of the financial year.

Averaged over the financial year, SSTs were very much warmer than average (i.e. in the highest 10% of historical observations since 1900) for much of the Australian region, and were highest on record across parts of the southern Maritime Continent region, much of the Arafura Sea and the Coral Sea, parts of the western Pacific Ocean, around New Zealand, and to the south of Tasmania.

June 2022–July 2023 finacial year mean sea surface temperature anomalies in the Australian region (as calculated from the 1961–1990 average).
The black line shows the 11-year moving average. The value for the 11-year average is positioned over the middle year of each 11-year block.
June 2022–July 2023 finacial year monthly sea surface temperature anomalies in the Australian region (as calculated from the 1961–1990 average).

La Niña, negative IOD and positive SAM

A combination of climate drivers influenced Australia's climate in 2022–2023: the second part of 2022 was influenced by a negative Indian Ocean Dipole (IOD); La Niña emerged in September 2022 and lasted until late summer; and the Southern Annular Mode (SAM) was mostly positive from mid-August to February.

These climate drivers contributed to development and maintenance of wetter conditions and played a part in Australia's second-wettest spring (September to November) 2022 on record (since 1900). The climate drivers occurred against the background of global warming.

La Niña

Signs of La Niña development appeared from late winter 2022. By the beginning of spring, key atmospheric and oceanic El Niño–Southern Oscillation (ENSO) indicators reflected an established La Niña.

In the tropical Pacific Ocean, sea surface temperatures had been cooling since July 2022 and crossed the La Niña threshold (-0.8 °C in the NINO3.4 region) in September. Other atmospheric indicators including the Southern Oscillation Index (SOI), trade wind strength, and equatorial cloudiness were also displaying patterns typical of a La Niña event.

La Niña conditions gradually strengthened and matured during October and November, before easing in early 2023.

La Niña events increase the chances of above average rainfall for much of northern and eastern Australia, particularly during winter and spring. La Niña also increases the chance of cooler than average winter-spring daytime temperatures for large parts of Australia.

The La Niña that started in September 2022 was the third consecutive event, following two La Niña events in 2020–2021 and 2021–2022. While back-to-back La Niña events are not uncommon and have occurred in approximately half of all past events since 1900, three consecutive La Niña events have previously occurred only three times: 1954–1957, 1973–1976, and 1998–2001. All three previous triple La Niña periods, and particularly 1973–1976, were associated with extended periods of above average rainfall, and widespread and prolonged flooding.

Indian Ocean Dipole (IOD)

During winter and spring, the Indian Ocean Dipole (IOD) was in a negative phase. Signs of negative IOD development began from late autumn 2022, with the IOD index tipping over negative IOD thresholds (i.e., at or cooler than −0.4 °C) by the end of June. The negative IOD event remained very strong from July through to September, before weakening over spring and dissipating in November, consistent with the usual timing of IOD event breakdown.

A negative IOD increases the chances of above average winter–spring rainfall for much of southern and eastern Australia, and likely contributed to the above average rainfall observed during late winter and spring. Maximum temperatures are also more likely to be below average across southern Australia during a negative IOD, while across northern Australia warmer than average temperatures are more likely. This temperature pattern was reflected in the June to November 2022 maximum temperatures.

Southern Annular Mode (SAM)

The Southern Annular Mode (SAM) was mostly positive from mid-August 2022 to February 2023. From March 2023 to the end of June, SAM was closer to neutral, with periods of positive and negative values.

Positive SAM typically enhances chances of above average rainfall over much of New South Wales during spring and increases the chance of above average rainfall for parts of eastern New South Wales, eastern Victoria, and south-eastern Queensland during summer. However, western Tasmania is typically drier as positive SAM shifts weather systems further south than their average path.

Positive SAM can be promoted by La Niña in the late spring to early summer, and it is likely the La Niña contributed to the persistent positive SAM during the latter part of 2022. This means the positive SAM typically enhances the wet signal of La Niña over parts of eastern Australia when they occur together.

Global Warming

Australia's climate is increasingly affected by global warming. Based on the Bureau's temperature dataset ACORN-SAT, Australia's climate has warmed by 1.47 ± 0.24 °C between 1910 (when national records began) and 2021, with most of the warming occurring since 1950.

The ocean waters around Australia have also warmed significantly over the past century, being consistently very warm over the past two decades. Every financial year since 1994-1995 has seen Australian ocean temperatures above the 1961–1990 average. Global ocean temperatures where the warmest on record in 2022–2023, exceeding the previous record warm financial year of 2021–2022. This background warming trend in land and ocean temperture can only be explained by human influence on the global climate.

Observations show that there has been an increase in the intensity of heavy rainfall events in Australia, with larger increases typically observed in the north of the country. A warmer atmosphere can hold more water vapour than a cooler atmosphere, and this relationship alone can increase moisture in the atmosphere by 7% for each 1 °C of global warming. Increased atmospheric moisture can also provide more energy for some processes that generate extreme rainfall events, which further increases the likelihood of heavy rainfall due to global warming.

Rainfall has increased across most of northern Australia since the 1970s, especially in the north-west during the northern wet season (October to April). However, year-to-year rainfall variability remains high for northern Australia.

In contrast, in the south-east of Australia (including the Murray–Darling Basin), April to October rainfall has declined by around 12% since the late 1990s, and by round 16% since 1970 over the south-west of Australia. This is due to a combination of natural variability on decadal timescales and changes in large-scale circulation caused by an increase in greenhouse gas emissions.

When climate drivers favour bringing rain-bearing weather systems over Australia, the increased likelihood of heavy rainfall events due to global warming may offset the decrease in average rainfall due to changes in atmospheric circulation. For southern Australia as whole, 2022 was the second-wettest April to October on record since 1900. 2022 was only the fourth time in the 21st century, after 2005, 2010, and 2016, that it was above the 1961–1990 average. In all 4 years, one or both of La Niña and the negative Indian Ocean dipole was active.

The influence of climate change on Australia's climate is discussed further in State of the Climate 2022.

Notable events

Regions
Event types

From 4 July, an East Coast Low brought several days of very heavy rain around Sydney that resulted in major flooding of the Hawkesbury–Nepean River and extended along the New South Wales coast. A natural disaster was declared for New South Wales following the flooding from heavy rainfall. Numerous locations set new daily July rainfall records, mostly in coastal areas from the Illawarra to the Mid North Coast, including around Sydney.

A series of cold fronts and low pressure troughs swept across southern and south-eastern Australia at the start of August as a deep and complex low pressure system passed to the south of the country. Periods of damaging winds, thunderstorms, heavy rainfall and generally cool conditions resulted with flood warnings issued for catchments across inland New South Wales, Victoria, and north-eastern Tasmania. Record-high daily rainfall for August was observed at a number of stations on the inland slopes and plains in New South Wales in the 24 hours to 9 am on 5 August. The Murrumbidgee River at Wagga Wagga reached minor flood levels as it continued to rise.

A complex low pressure system crossing the Great Australian Bight extended cold fronts over south-east Australia and into Queensland during 11 and 12 August. The low developed into a Tasman Low, bringing strong winds and heavy rain to the south-east and localised reports of hail in metropolitan Melbourne. The Tasman Low stalled in Bass Strait on the 13th and 14th, bringing multi-day rainfall totals of 50 to 100 mm over much of Tasmania and Gippsland in Victoria. A number of sites in both states set daily rainfall records for August during this period, and several rivers in eastern Tasmania and Gippsland in Victoria experienced minor to major flooding.

During the middle of September, a deep low pressure system was well south of the Great Australian Bight was associated with a complex system of cold fronts and troughs extending across south-east Australia. Cloud and embedded thunderstorms brought heavy rainfall over some areas. Significant rain fell on the inland side of the ranges in north-eastern New South Wales and the Queensland border region.

Renewed rises in river levels were observed in many catchments in inland New South Wales, with major flood levels reached in some rivers. Minor to moderate flood levels persisted across multiple rivers in New South Wales until the end of September. Minor to moderate flooding also continued in parts of Victoria and Tasmania during September.

Later in September an offshore low brought onshore flow and locally intense rainfall to coastal areas from the New South Wales Northern Rivers district to south-eastern Queensland from the 22nd, resulting in rises in river levels along many already flooded rivers.

Flooding occurred from the first week of October as rain fell onto already wet soils and full or close to full catchments. In the Murray–Darling Basin the flooding occurred over prolonged periods, or on multiple occasions. Throughout the month a number of low pressure systems or surface troughs crossed southern or eastern Australia. These connected with tropical air masses from the north, which were laden with moisture drawn from exceptionally warm ocean waters. This combination led to storms and periods of prolonged, and at times very heavy, rainfall over the eastern states and parts of the interior.

A low pressure system south of the mainland linked up with tropical moisture from around 12 October, forming an extensive, slow-moving rain band over south-east Australia. Major flooding along the Maribyrnong River resulted in evacuations of inner Melbourne suburbs, while major flooding also led to inundation in a number of other cities and towns including Shepparton–Mooroopna, Rochester, and Echuca. A very large number of stations across central and northern Victoria and northern Tasmania set daily rainfall records for October during the 24 hours to 9 am either on the 13th or the 14th. Major flooding continued along multiple rivers in central and northern Victoria well into the following week, with further evacuation orders in some places, and landslips contributing to road closures in addition to those obstructed by water.

A large number of stations in New South Wales, Victoria, eastern South Australia, and northern Tasmania set daily rainfall records for October between the 20th and 27th as a low pressure system developing over New South Wales was overtaken by a strong cold front crossing further south, before the low reformed and became slow-moving over Tasmania. Thunderstorms and moderate to heavy rainfall affected large areas. On the 25th suburbs in Melbourne's outer east were hit by storms and flash flooding, with particularly intense rainfall observed in Lilydale and the surrounding area.

Significant flooding continued to affect much of eastern Australia in November, following on from major floods earlier in spring. Floodwaters continued to move downstream in the Murray–Darling Basin, with renewed rises in river levels from rain during the month. By the end of the month, towns affected by major flooding included Brewarrina, Bourke, Condobolin, Euabalong, Hillston, Hay, Balranald, and Wentworth.

At the start of November, a cold front interacted with moist tropical air bringing rain across inland New South Wales and eastern Queensland. Major flooding resulted along the Lachlan and Murrumbidgee rivers, with evacuations ordered for Forbes and parts of Wagga Wagga. Further north, major flood levels were reached at this time along parts of the Namoi, Barwon, and Darling rivers.

On the 13th, thunderstorms in a cloudband affected much of the Central West of New South Wales, including Forbes again. Many sites in the region set November daily rainfall records as the storms caused flash flooding across the Central West including at Eugowra.

On 12 November severe thunderstorms embedded in a cloudband struck southern South Australia with up to 423,000 lightning strikes and wind gusts up to 109 km/h. A number of sites in the Mount Lofty Ranges and on the Fleurieu Peninsula set daily rainfall records for November. The storms caused widespread significant power outages across metropolitan Adelaide. An interstate transmission line was also damaged.

Following extended periods of flooding during spring, major flooding continued as flood waters progressed through a number of inland rivers in the south-eastern mainland states and southern Queensland. Extended periods of major flooding continued to affect the Darling, Namoi, Barwon, Macquarie, and Murray–Darling rivers during December.

A Special Climate Statement is being prepared for the floods affecting eastern Australia in spring 2022.

Ex-TC Ellie resulted in significant flooding on the Fitzroy River, which reached its highest levels on record, peaking at 15.81 m on the afternoon of 4 January at Fitzroy Crossing, isolating the town and many other nearby communities and significantly damaging the Great Northern Highway bridge.

Several days of locally heavy rainfall and thunderstorms affected many areas of Queensland. Major flooding resulted along the Georgina River between Roxborough Downs and Glenormiston. Burketown, Doomadgee, and Gregory remained isolated into mid-January due to the high levels of the Nicholson/Gregory and Leichhardt river systems.

Severe thunderstorms with locally heavy rainfall resulted in flooding in northern and central Queensland. Townsville Aero recorded 160.2 mm in the 24 hours to 9am on 15 January, whilst Proserpine Airport recorded 316.6 mm in the 24 hours to 9am on 16 January 2023, its highest daily rainfall total since 14 January 2008.

Moderate to major flooding that started in 2022, continued along the Murray–Darling River system, with major flooding along the Darling River throughout most of January.

Heatwaves affected eastern Australia in early February, particularly along the Queensland coast. Severe heatwave conditions affected south-eastern Queensland, including Brisbane and the Sunshine Coast. Some stations in coastal south-east Queensland observed a record high daily maximum temperature for February.

On 3 February, an afternoon storm brought high winds that left significant damage across Port Macquarie, with trees and powerlines downed, and roofs ripped from buildings. Thousands of homes and businesses in and around Port Macquarie's CBD lost power.

Tropical Cyclone Gabrielle was a category 3 system that formed in the Coral Sea well east of the Queensland coast before intensifying and moving south-east towards Norfolk Island. It impacted Norfolk Island overnight from 11 to 12 February causing widespread damage.

On 13 February, heavy rainfall caused flash flooding in south-east Queensland and north-east New South Wales as severe thunderstorms moved through the area. Large to giant hail (2 to 5 cm diameter) was observed near Highfields in New South Wales and Stanthorpe and Kingsthorpe in Queensland, while flash flooding was observed in a number of areas, including parts of Brisbane and Maroochydore.

Storms and widespread heavy rain in the northern tropics associated with a monsoon trough and a tropical low (16U) started in the last week of February and continued throughout the first ten days of March. Ten-day totals of 400 to 800 mm were recorded in an area of the Carpentaria and Barkly districts in the Northern Territory and in Queensland's Gulf Country and North-West districts. This event resulted in major flooding along the several rivers across the eastern Northern Territory and north-western Queensland, leading to evacuation of some communities and the closure of many transport routes. More than half a metre of rain in 2 days led to record-high flood levels around Burketown in the Gulf Country; most of the Burketown's population was evacuated, while surrounding areas suffered heavy livestock losses.

On 12 March, more than 100 mm fell in 24 hours at some locations in the South West Slopes region of southern New South Wales, causing flash flooding. High daily rainfall totals lead to river rises and flooding along Muttama Creek. The State Emergency Services issued an emergency evacuation order for 880 properties along the creek.

A series of cold fronts crossed south-eastern Australia between 6 and 10 March, bringing gusty winds and daily maximum temperatures up to 10 °C below average. Thunderstorms produced rain and showers in much of Tasmania, Victoria and south-western New South Wales. For western Tasmania, rainfall totals over this period were generally between 50 and 100 mm, with snow falling to relatively low levels.

High temperatures and strong winds resulted in multiple grassfires and bushfires across Victoria and New South Wales, with hundreds of firefighters deployed and total fire bans in place across Victoria and for much of New South Wales and South Australia.

Strong wind gusts brought down trees resulting in power blackouts in parts of Southern Australia. Thousands of properties, mostly across Greater Adelaide and the Adelaide Hills were without power on the 20th.

Tropical moisture combined with weather systems including a tropical low to the west of Western Australia, brought several days of widespread rainfall, showers and storms to large parts of Australia. In New South Wales three-day rainfall totals to 9am on the 30th were generally between 50 and 80 mm in much of the Northern Tablelands and Mid North Coast, with locally higher totals, and between 40 and 60 mm across South West Slopes. Severe thunderstorms brought heavy rain, lightning, gusty winds and hail to Tamworth region.

Thunderstorms brought heavy rain and daily totals of more than 50 mm to Greater Sydney, resulting in flash flooding that blocked roads and disrupted train lines. Sydney (Observatory Hill) recorded 115.4 mm of rain in the 48 hours to 9am on 3 April.

Cold fronts generated thunderstorms, showers and widespread rainfall in south-eastern South Australia, most of Victoria and Tasmania, and parts of New South Wales and Queensland. A low pressure trough triggered severe thunderstorms which brought large hail to some areas in south-western Queensland and New South Wales on the 7th.

A cold front brought gusty winds, isolated thunderstorms and polar air to south-eastern states. On the 7th, Cooma Airport (NSW) had a maximum temperature of 2.7 °C, a May record by 2.2 °C, and the fifth-lowest daily maximum temperature for this site in any month. In south-east New South Wales and north-east Victoria snow fell down to 700 m, while Alpine areas had 10 to 20 cm of snow. Parts of the Australian Capital Territory and Victoria reported heavy hail on the 7th.

A cold front that crossed Tasmania overnight between the 20th and 21st brought damaging to destructive winds with gusts in excess of 100 km/h to much of Victoria, Tasmania and southern New South Wales. The strongest wind gusts observed were 137 and 126 km/h recorded at Wilsons Promontory Lighthouse (Victoria) and Tasman Island (Tasmania) respectively. Strong winds caused disruptions to electricity supplies and widespread power outages affected various parts of Tasmania.

Severe thunderstorms across the Hunter coast and Newcastle area in the afternoon of the 26th brought flash flooding, large to giant hail, waterspouts (near Wiliamstown RAAF) and heavy rainfall which locally exceeded 50 mm in one hour. More than 2000 customers in the suburbs of New Castle West, The Junction, Bar Beach and Merewether were without power.

A cold front dragged in tropical moisture and brought thunderstorms and heavy rain to parts of eastern South Australia, Victoria, southern New South Wales and northern Tasmania on the 7th. Numerous sites in Victoria's north-east recorded daily rainfall totals of more than 100 mm, while large areas of northern Tasmania recorded rainfall totals of 50-100 mm. Minor to Moderate flood warnings were issued for catchments in north-east Vic and the Yarra River and a Major flood warning for the King River.

Where to find more information

The Financial year climate and water statements provide a range of climate and water information at a national level.

Climate summaries are produced for each month and season, for Australia nationally and for the states and most capital cities. Special Climate Statements are produced on an occasional basis, and provide a detailed summary of weather/climate events which are unusual in the context of the climatology of the affected region.

The National Water Account includes detailed water information for eleven nationally significant water management regions. The Groundwater Information Suite provides data on bore water levels and trends, and associated data on hydrogeology and groundwater management.

Data information

For more information, find area average data and timeseries for the financial year period, with maps for the 12-months periods ending June available from recent conditions.

Data currency

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. The use of current and historical climate information allows for comparison of climate impacts from one year to the next and aligns with other reporting processes that occur over financial year periods.

Data sources

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.

This statement was prepared using the following sources:

A note on base periods

In climatology a baseline, or long-term average, is required against which to compare changes in climate over time. The Bureau uses the 1961–1990 period as the climate reference period for the Annual Climate Statement and other climate monitoring products.

A minimum 30 years of data 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 comparable to the first 30-year period where there is good global coverage of climate data, and is thus used as a benchmark for reporting climate change allowing consistent comparison of national temperature observations 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.

The choice of base period is a convention. It has no bearing on the calculation of trends over time, or the ranking of one year compared to all other years in a dataset.

Product code: IDCKGC6AR0