Drought
Rainfall deficiencies and water availability

Low rainfall in the west and east flanking high falls from the Kimberley to Tasmania

June rainfall was 24.6% above the 1961–1990 average for Australia. It was above average for a broad band stretching from the north-west to the south-east of the continent and Tasmania and for parts of the southern coast of Western Australia. Rainfall was below average (in the highest 30% of all observations since 1900) for most of central and eastern Queensland, coastal New South Wales extending inland and into far eastern Victoria, and for a large part of north-west Western Australia

Above average June rainfall along the southern coast of Western Australia reduced areas of short-term rainfall deficiencies west of Esperance. Many areas of the east and west already experiencing rainfall deficiencies had below average June rainfall.

For the 7-month period starting December 2022, the south-east corner of Queensland has areas of serious rainfall deficiencies (totals in the lowest 10% since 1900) extending inland from Wide Bay and Burnett across the south of the Central Highlands and Coalfields and into Maranoa and Warrego districts. Areas with severe rainfall deficiencies (totals in the lowest 5% since 1900) extend across most of Wide Bay and Burnett into the north of the Darling Downs with pockets elsewhere. In north-east New South Wales, an area of serious deficiency extends inland from the west of the ranges, with pockets of serious and severe deficiency east of the Divide and in the Hunter District. Western Australia has small areas of serious and severe deficiencies in the Gascoyne, Central West, South West and Eucla districts.

For the 19-month period starting December 2021, deficiencies persist on the south-west coast of Tasmania and in a small pocket of far south-west Western Australia.

The long-range forecast released on 6 July 2023 indicates that for August to October, below median rainfall is likely (60% to 80% chance) for most of Australia, increasing to very likely (greater than 80% chance) for large parts of Victoria, south-east South Australia and south-west Western Australia. Above median rainfall is forecast for far northern Queensland. Large parts of eastern and south-western Western Australia are at least twice as likely to receive unusually low rainfall (unusually low rainfall equates to the driest 20% of August to October periods from 1981 to 2018). The chance of unusually low rainfall increases to four times as likely for large areas of south-east South Australia, south-west Victoria and far south Western Australia.

State of the Climate 2022 reported that there has been a shift towards drier conditions across the south-west and south-east Australia, especially for 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 7 months since December 2022

For the 7-month period starting December 2022, the south-east corner of Queensland has areas of serious rainfall deficiencies (totals in the lowest 10% since 1900) extending inland from Wide Bay and Burnett across the south of the Central Highlands and Coalfields and into Maranoa and Warrego districts. Areas with severe rainfall deficiencies (totals in the lowest 5% since 1900) extend across most of Wide Bay and Burnett into the north of the Darling Downs with pockets elsewhere. In north-east New South Wales, an area of serious deficiency extends inland from the west of the ranges, with pockets of serious and severe deficiency east of the Divide and in the Hunter District. Western Australia has small areas of serious and severe deficiencies in the Gascoyne, Central West, South West and Eucla districts.

Deficiencies for the 19 months since December 2021

For the 19-month period starting December 2021, deficiencies persist on the south-west coast of Tasmania and in a small pocket of far south-west Western Australia.

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Soil moisture

Root-zone soil moisture (soil moisture in the top 100 cm) was below average, (in the lowest 30% of all observations since 1900), across a wide band of south-west Western Australia into western South Australia, parts of the east of the Northern Territory and along the east of Australia including much of Queensland, New South Wales, far-eastern Victoria and part of eastern Tasmania. Areas of very much below average soil moisture were distributed within these regions, particularly in Western Australia and Queensland.

Compared with last month, soil moisture decreased for most of the west and east of Australia.

Evaporative stress

Evaporative stress for the 4 weeks ending 30 June 2023 is elevated (index is negative) in Western Australia between the Kimberley District and the south-west of the state, much of the Northern Territory, most of Queensland, inland and coastal New South Wales, particularly in the Hunter District, the north-west and parts of eastern Victoria, and the west and parts of the east of South Australia.

Compared to last month, ESI has decreased in intensity along parts of the southern coast of Australia, the south-eastern ranges, and in Tasmania.

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

• June rainfall was 24.6% above the 1961–1990 average for Australia. It was above average for a broad band stretching from the north-west to the south-east of the continent and Tasmania, and for parts of the southern coast of Western Australia.
• Rainfall was below average, (in the lowest 30% of all observations since 1900), for most of central and eastern Queensland, coastal New South Wales extending inland and into far eastern Victoria, and for a large part of the north-west of Western Australia.
• For the period commencing December 2022, areas experiencing serious or severe rainfall deficiencies (totals in the lowest 10% of observations since 1900), include parts of the south-east quarter of Queensland, areas in the north-eastern quarter of New South Wales, and pockets along the south-western coast of Western Australia.
• Soil moisture was below average, (in the lowest 30% of all observations since 1900), across a wide band of south-west Western Australia into western South Australia, and much of eastern Australia, particularly in Queensland.
• Low streamflows were observed mostly at sites in the south and central west of Western Australia, in the north-west of the Murray–Darling Basin, and coastal New South Wales and Queensland.
• Storage levels remain low in some parts of south and central Queensland, central Tasmania, parts of New South Wales, and in urban areas of Perth.
• For August to October, below median rainfall is likely to very likely (60% to greater than 80% chance) for much of the south and east of Australia.

Streamflows high in parts of the north and south Australia; low in parts of east coast Australia and central Western Australia

In June, areas of average to below average rainfall and soil moisture, and subsequent low streamflow conditions, were largely concentrated in central and eastern Queensland, coastal New South Wales and central parts of Western Australia. Streamflow was average at 40% of the 860 sites across the country (based on records since 1975). Below average streamflow was observed at 17% of the 860 sites, mostly associated with below average rainfall and drier catchment conditions in the west of Western Australia, north-west of the Murray–Darling Basin, coastal parts of New South Wales and eastern parts of Queensland.

In June, above to very much above average streamflow was observed at 41% of sites, mainly in southern Australia, including southern areas of the Murray–Darling Basin, western Victoria, South Australia, and scattered sites in the south and north-west of Western Australia and the wet tropics in Queensland and the Northern Territory. In June, moderate to minor flood warnings were issued for rivers in north Tasmania and northern Victoria, and a downstream movement of floodwater resulted in above average streamflows in rivers in these areas.

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

In June, rainfall and soil moisture were average to below average rainfall, particularly in eastern and western Australia, with higher than average rainfall and soil moisture in a central strip from the north-west to south-east of the continent, which resulted in a slight increase in some storages from May. By the end of June, the total water storage in Australia (across Australia's 306 public storages) was at 78.1% of capacity, slightly higher than the previous month, and higher than at the same time last year. Despite most of Australia's major storages being high, storage volumes remain low in several locations, particularly in south and central Queensland, central Tasmania, parts of New South Wales, and urban areas of Perth.

Combined storages in the Murray–Darling Basin were 92.2% full at the end of June, an increase of 2.8% from the same time last year, due to average to very much above rainfall in western inland regions of New South Wales.

In June, in Western Australia most of the interior of received average to below average rainfall and experienced dry catchment conditions, however parts of the south coast received higher than average rainfall, resulting in a slight increase in some storage levels. Perth's surface water storages were below half capacity (47.1% full) at the end of June, a 1.3% increase from May, and a 1.3% decrease from the same time last year, when it sat at 48.4%. 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.

June's lower than average rainfall across most of south-eastern Queensland and dry catchment conditions resulted in decreased storage volumes from last month. Water levels in the Beardmore storage remain low, decreasing to 15.3% by the end of June (a significant decrease from 101% at the same time last year). Water levels in the Nogoa Mackenzie system in central Queensland remain low, slightly decreasing to 40.1% by the end of June, but up from 22.7% at the same time last year. In central Queensland, water storage in Fairbairn was below half capacity at the end of June, at 39.5%, although it was an increase from same time last year (21.6%).