Drought
Rainfall deficiencies and water availability

Wet November eases short-term rainfall deficiencies in the east

November rainfall was 37.8% above the 1961–1990 average for Australia as a whole, and it was above or very much above average for most of the Northern Territory, Queensland and New South Wales, large areas in Victoria, south-eastern and north-western South Australia and southern and eastern Western Australia.

Rainfall was below or very much below average for Tasmania, parts of the Gascoyne district and coastal south-west Western Australia, West Coast, Eyre Peninsula and North West Pastoral districts (South Australia), Victoria's South West district, western Top End in the Northern Territory and Peninsula and North Tropical Coast (Queensland).

For Australia as a whole, spring rainfall was 20.1% below the 1961–1990 average, the lowest for spring since 2019. All states and territories had below average spring rainfall. For Tasmania, it was the fifth-driest spring on record. The season began with Australia's driest September on record, followed by the fifth-driest October on record.

Rainfall in spring was below average for large parts of the southern Western Australia, much of South Australia, Tasmania and south-western Victoria, areas in the north-eastern and north-western New South Wales, coastal parts of Queensland including the Cape York Peninsula, and parts of the western Top End in the Northern Territory. Rainfall was very much below average for spring (in the driest 10% of years since 1900) for parts of Western Australia's Southern Interior district and western and southern coasts extending inland, most of south-eastern South Australia, northern Tasmania, parts of western Victoria, the Cape York Peninsula (Queensland), and a small area in the far north-west of the Top End (Northern Territory).

Spring rainfall was above average for scattered areas across the Northern Territory, Queensland and New South Wales, parts of eastern Victoria, and some smaller areas in Western Australia. Rainfall was very much above average for spring (in wettest 10% of years since 1900) for Victoria's east and South Gippsland.

For the 4-month period since August 2023, areas of rainfall deficiencies have generally eased following above average November rainfall across much of Australia. Deficiencies remain along coastal south-west Western Australia, coastal and some inland areas in South Australia, south-west Victoria, northern Tasmania, and small areas in Queensland, particularly in the Wide Bay and Burnett and Central Highlands and Coalfields districts and on the western Cape York Peninsula around Weipa.

For the 7-month period since May 2023, areas of rainfall deficiencies extend across most of the west of Western Australia, and along parts of southern and south-eastern coastal Australia, as well as pockets of deficiencies in south-central Victoria, eastern Tasmania and the far north of Queensland and the Northern Territory.

For the 12-month period since December 2022, areas of rainfall deficiency have eased slightly in the south-eastern corner of Queensland and north-eastern New South Wales, but increased in area in severity in Western Australia, particularly along the coast between Perth and Carnarvon.

Since October, areas of deficiency have generally cleared or eased in northern and eastern Australia but have persisted along the southern coast and become more severe in northern Tasmania.

The long-range forecast released on 30 November 2023 indicates that below median rainfall for December 2023 to February 2024 is likely to very likely (60% to greater than 80% chance) for most of Western Australia, northern and central Northern Territory, the northern half of Queensland, and small areas of coastal New South Wales. For December to February, large parts of inland Australia have a near equal chance of above or below average rainfall. However, if above average rainfall occurs, it is unlikely to be widespread.

State of the Climate 2022 reported a long-term shift towards drier conditions across the south-west and south-east of Australia, particularly during the cool season months of April to October. 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. Since the 1990s, in the absence of strong 'wet' drivers, cool season (April to October) rainfall in southern Australia has generally been lower than average.

Deficiencies for the 4 months since August 2023

For the 4-month period since August 2023, areas of severe or serious rainfall deficiencies (totals in the lowest 5% or 10% of periods since 1900) persist along the south-west coast of Western Australia including pockets of lowest on record rainfall, coastal areas of South Australia and some eastern inland areas, south-west Victoria, northern Tasmania and small areas in Queensland, particularly in the Wide Bay and Burnett and Central Highlands and Coalfields districts and on the western Cape York Peninsula around Weipa. There are also small areas of rainfall deficiency in the Northern Tablelands and North West Slopes and Plains districts in New South Wales, and the western Top End of the Northern Territory.

Since October, rainfall deficiency areas have been cleared or significantly reduced in northern, central, and eastern Australia following above average November rainfall across much of Australia.

Deficiencies for the 7 months since May 2023

For the 7-month period since May 2023, areas of severe or serious rainfall deficiencies (totals in the lowest 5% or 10% of periods since 1900) extend across most of the west of Western Australia, including a large area of lowest on record rainfall in the Gascoyne and Central West districts. Deficiency areas include part of the Southern Interior district, and along the southern coast from the Eucla district in Western Australia to Kangaroo Island in South Australia. In the east, deficiency areas extend from far-eastern Victoria, along most of coastal New South Wales and into Wide Bay and Burnett and Central Highlands and Coalfields districts in Queensland. There are also small deficiency areas in south-central Victoria, part of the central-east coast of Tasmania, around Darwin in the Northern Territory, and in the Cape York Peninsula in Queensland.

During November, rainfall deficiencies eased or contracted in the north and east of Australia, particularly in south-eastern Queensland and eastern New South Wales.

Deficiencies for the 12 months since December 2022

For the 12-month period starting December 2022, country with severe or serious rainfall deficiencies (totals in the lowest 5% or 10% of periods since 1900) includes areas along the coast of Western Australia between Carnarvon and Busselton, the Eucla district, and some inland areas in the south-west. In eastern Australia, large areas of deficiency are concentrated in the south-eastern corner of Queensland and north-eastern New South Wales. Isolated pockets of rainfall deficiencies occur in southern areas of South Australia, central and south-eastern Tasmania.

Since October, the extent and severity of 12-month rainfall deficiencies has decreased in the south-eastern corner of Queensland and north-eastern, central and the south coast of New South Wales. In Western Australia, 12-month rainfall deficiency areas have increased in area and severity, with lowest on record totals for coastal areas of the Central West and Gascoyne districts.

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Below average soil moisture across much of southern Australia and the east coast

November root-zone soil moisture (soil moisture in the top 100 cm) was below to very much below average (driest 30 to 10% of years since 1911) across large areas of southern Australia, along most of the east coast, part of the Top End, and patchy inland areas in all states. It was particularly dry in areas along the south coast, northern Tasmania, south-eastern New South Wales. There were pockets of lowest on record soil moisture in the south of Western Australia.

Since October, soil moisture increased across most of Australia.

High evaporative stress across southern Western Australia and south-eastern Queensland

Evaporative stress for the 4 weeks ending 30 November 2023 is elevated (index is negative) across much of Western Australia and South Australia, across western Victoria, Tasmania, much of New South Wales, the eastern coast of Queensland, and the Top End in the Northern Territory.

Compared to last month, the evaporative stress index has increased in intensity in central South Australia and the west of Victoria, across Tasmania and the Top End of the Northern Territory. It has eased in much of south-eastern Queensland, northern and coastal New South Wales, and in pockets of south-west Western Australia.

See the journal publication for further details on calculation and use of evaporative stress index in drought monitoring.

• November rainfall was 37.8% above the 1961–1990 average for Australia as a whole, and it was above average for all states and territories except Tasmania.
• Spring rainfall was 20.1% below average for Australia as a whole, the lowest for spring since 2019. It was below average for large parts of southern Western Australia, much of South Australia, Tasmania and south-western Victoria, areas in north-eastern and north-western New South Wales, coastal parts of Queensland including the Cape York Peninsula, and parts of the western Top End in the Northern Territory.
• Above average November rainfall eased 4-month rainfall deficiencies in much of northern and eastern Australia, however areas of deficiencies persist in all states, particularly in the south.
• There are longer term rainfall deficiencies, on the 7- and 12-month periods, particularly in Western Australia and parts of the southern and east coast.
• Soil moisture was very much below average in southern Australia, areas in Western Australia and along the eastern and northern coasts.
• Low streamflows were observed mostly at sites in central and north-east Queensland, north-eastern New South Wales, south-west Western Australia, South Australia and western Victoria and Tasmania.
• Storage levels remain low in some parts of southern and central Queensland, eastern parts of New South Wales, central Tasmania, western Victoria and urban areas of Perth.
• For December 2023 to February 2024, below median rainfall is likely to very likely (60% to greater than 80% chance) for western and northern Australia, and small areas of coastal New South Wales

Streamflows low in south eastern Australia and southern Australia

Low streamflow in the southern Australia was associated with the areas of below average rainfall and soil moisture conditions for November. Below to very much below average streamflow was observed at 37% of the 827 sites, mostly associated with below average rainfall and drier catchment conditions in September and October, particularly in the south-east and scattered sites in the central and north-east Queensland, north-eastern New South Wales, most of the sites in south-west of Western Australia, South Australia and western Victoria. Streamflow was average at 50% of the 827 sites across the country (based on records since 1975).

Due to above to very much above average rainfall in eastern and norther Australia in November, above to very much above average streamflow was observed at 13% of sites, mainly scattered sites in the Northern Territory, north wet tropics of Queensland and north and south of New South Wales.

In late November, moderate to major flood warnings were issued for rivers in south-west Queensland, parts of Gippsland and Snowy River Victoria and south-east NSW, and downstream movement of floodwater resulted in higher-than-average streamflows in rivers in these areas.

Overall high storage levels across the country, but low storage levels at several locations

In November, despite average to above average rainfall mostly in eastern and northern Australia, very much below average soil moisture, particularly for southern Australia, eastern coastal area of Queensland; and large parts of Western Australia, resulted in a slight decrease in some storage levels from October. By the end of November, the total water storage level in Australia (across Australia's 306 public storages) was at 75.3% of capacity, slightly lower (1.1%) than the previous month, and 1.6% lower than at the same time last year. Most of Australia's major storages remain high, but storage volumes are low in several locations, particularly in south and central Queensland, inland and eastern parts of New South Wales, central Tasmania, western Victoria and urban areas of Perth.

Combined storages in the Murray–Darling Basin were 88.7% full at the end of November, a slight decrease, by 2.1%, from October, and also a decrease of 10.3% from the same time last year. Menindee Lakes decreased to 67.7% full at the end of November, a 5.6% decrease from October and a 33.4% decrease from the same time last year (101.5%).

Perth's surface water storages remained below the half capacity (49.1% full) at the end of November, a 2.7% decrease from October, and a 9.0% decrease from the same time last year (58.1%). Long-term declines in surface water inflows to Perth's storages means the city's water supply is generally more reliant on desalination and groundwater sources.

Despite above average rainfall in November there was well below average rainfall from August to October, and dry catchment conditions across large parts of south-eastern Australia, including parts of south-eastern Queensland, resulted in decreased volumes for many storages (decreased volumes for 44 storages in the North East Coast drainage division) from last month. Water levels in the Lake Awoonga in south eastern Queensland remain low, capacity (53.6% full) at the end of November, a 1.3% decrease from October and a 9.8% decrease from the same time last year (63.4%). In central Queensland, water storage in Fairbairn was below half capacity at the end of November, at 30.6%, a slight decrease (0.7% ) from October, and it was a 9.2% decrease from same time last year (39.8%).

Due to below average rainfall and dry catchment conditions in November, water storage in Rocklands Resevoir in western Victoria was slightly decreased to 58.0% full by the end of November, a 2.2% decrease from October and a decrease from same time last year (70.5%).