Drought
Rainfall deficiencies and water availability

Much drier than average across large areas of southern Australia

May rainfall was below average to very much below average (in the lowest 10% of Mays since 1900) for:

• most of southern Western Australia
• most of South Australia
• most of Victoria
• northern and western Tasmania
• western New South Wales
• areas surrounding the Gulf of Carpentaria in Queensland and the Northern Territory.

It was the seventh-driest May on record for Victoria, with area-averaged rainfall 71% below average, the driest since 2005.

Further details: Monthly climate summaries, Latest National climate summary

Autumn cool season rainfall

Southern Australia receives most of its annual rainfall in the cooler months from April to October. Autumn rainfall was below average for much of south-eastern Australia and large parts of Western Australia. Tasmania and Victoria had their third and ninth-driest autumn on record, respectively since 1900. These drier than average conditions were amplified by warm temperatures. Victoria had its warmest autumn on record, New South Wales and Western Australia had their second-warmest, and for South Australia it was the third-warmest autumn on record.

Recent weather patterns

So far in 2025, weather patterns across southern Australia have been dominated by slow-moving high pressure systems. This is a continuation of weather patterns seen throughout much of 2024. These slow-moving high pressure systems have resulted in persistent warm and dry conditions. There have been fewer outbreaks of cold air or rain-bearing weather systems, like the deep low pressure system that crossed southern Australia towards the end of May.

More broadly, the Southern Annual Mode (SAM) has been positive for most of 2025. This has resulted in high pressure systems being further south than usual for this time of year across the southern hemisphere.

Persistent low rainfall in recent months

Persistent low rainfall conditions have affected much of southern Australia in recent seasons. Since early 2023, rainfall deficiencies (rainfall totals in the lowest 5% since 1900) have developed in Western Australia, South Australia, Victoria and Tasmania. Rainfall deficiencies have been especially significant in regions with western-facing coastlines, including the south-east of South Australia. During this time, soil moisture content, runoff, streamflow and water storage levels have all decreased across much of southern Australia.

Maps: Recent and historical rainfall maps

Climate change

State of the Climate 2024 has indicated that there has been a shift towards drier conditions across southern Australia, especially for the cool season months from April to October. While some areas can have above average rainfall in some seasons, for southern Australia as a whole, April to October rainfall has been below the historical (1961–1990) average in 24 the last 30 years since 1994.

The declining trend in rainfall is associated with a trend towards higher surface atmospheric pressure in the region and a shift in large-scale weather patterns. There have been more highs, fewer lows and a reduction in the number of rain-producing lows and cold fronts. Over the southern Australia region, there has been an increase in density, and therefore frequency, of high pressure systems across all seasons.

Long-range forecast for July to September

The long-range forecast, released on 5 June 2025 for July to September 2025 shows:

• Rainfall is likely to be above average for much of Australia especially from August, except in the south-east and west.
• Warmer than average days and nights are very likely across most of Australia.

Deficiencies for the 5 months since January 2025

For the year-to-date 5-month period since January 2025, areas with severe or serious rainfall deficiencies (rainfall totals in the lowest 5% or 10% of periods, respectively, since 1900) extend across:

• south-eastern South Australia
• much of Victoria except for parts of the state’s north and East Gippsland
• most of Tasmania
• much of the west coast of Western Australia, extending inland, and a small pocket in the central interior
• parts of western New South Wales

Areas with lowest on record rainfall include:

• areas near the coast in the Gascoyne, Central West and Lower West districts of Western Australia,
• across most of the agricultural areas in South Australia
• western Victoria, from the north-west to Cape Otway and part of South Gippsland
• the north-western third of Tasmania

Since April, rainfall deficiency areas have expanded and intensified in all southern states and have extended into parts of western New South Wales.

Deficiencies for the 16 months since April 2023

For the 16-month period since February 2024, areas with severe or serious rainfall deficiencies (rainfall totals in the lowest 5% or 10% of periods, respectively, since 1900) extend across:

• agricultural regions of South Australia
• Victoria, except areas along the northern border and east Gippsland
• small areas of the eastern ranges and southern New South Wales
• coastal western Tasmania, Bass Strait islands and a small area of the east coast
• areas along coastal south-west Western Australia.

Areas with lowest on record rainfall include:

• most of the agricultural areas of South Australia
• from west facing coasts in Victoria, extending inland to the far north-west
• part of the north-west coastline in Tasmania.

Compared to April, areas of rainfall deficiency increased in severity and extent in southern Australia, with areas of lowest on record rainfall expanding in South Australia and Victoria.

Deficiencies for the 26 months since May 2023

For the 26-month period since April 2023, which includes the last two cool seasons, areas with severe or serious rainfall deficiencies (rainfall totals in the lowest 5% or 10% of periods, respectively, since 1900) extend across:

• large areas in the south-west and west of Western Australia
• agricultural regions of South Australia
• south-western Victoria and small areas in the east
• parts of the west and east coasts of Tasmania, the Bass Strait islands, and some inland areas
• a small area of the south-eastern ranges in Victoria and New South Wales.

Areas with lowest on record rainfall include:

• a large region extending inland around Perth in Western Australia
• areas of the Yorke Peninsula, Mid North and Murraylands districts in South Australia
• the coastline from Warrnambool to Cape Otway in Victoria.

Since April, rainfall deficiency areas have increased in severity in Western Australia, South Australia, Victoria and Tasmania.

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Below average soil moisture continues in the south and west

May root zone soil moisture was below to very much below average (in the lowest 10% of Mays since 1911) in:

• large parts of the west and south of Western Australia
• most of South Australia excluding the north
• much of Victoria
• Tasmania
• parts of southern and western New South Wales.

Long-term deficits continued across much of the southern coastal region of Australia with areas of very much below average soil moisture expanding from April and pockets of lowest on record soil moisture emerging. This is largely because soil moisture is typically starting to increase at this time of year in those areas, but May soil moisture remained similar or decreased. While below average, soil moisture was high in much of the west coast of Tasmania, but lower in the north-west where root zone soil moisture was around 40% below the typical column saturation for May. Soil moisture deficits also expanded and intensified in western parts of Western Australia, however, with the exception of the south-west, average soil moisture is generally low in this region during May.

Low soil moisture for long periods of time is an indicator of agricultural drought. It can affect ongoing crop growth, and the pasture growth required for livestock.

With significant rainfall events in the north and along the east coast, soil moisture has remained above average. Root zone soil moisture for May was above 80% saturation of the soil column for coastal northern New South Wales.

High evaporative stress across much of southern Australia

Evaporative stress for the 4 weeks ending 31 May 2025 was elevated (negative Evaporative Stress Index (ESI)) in:

• central and southern South Australia
• Victoria excluding the far east
• Tasmania
• parts of western and south-east New South Wales
• Western Australia, excluding parts of the south and north
• central Northern Territory.

While the extent of soil moisture stress remained similar to April, areas of significantly elevated (below −2) ESI expanded in south-eastern South Australia, Victoria, southern New South Wales and northern Tasmania.

See this journal publication for further details on calculation and use of the ESI in drought monitoring.

Rainfall deficiencies and water storage at the end of May

• May rainfall was below average across much of southern Australia and above average across large parts of northern Australia and eastern New South Wales.
• Rainfall deficiency areas increased in extent and severity across all states in southern Australia and began to establish in parts of western New South Wales.
• Areas of soil moisture deficiency continue across much of southern and western Australia.
• Streamflow was low at many sites in southern and western Australia.
• Many water storages in southern states were 10 to 50% lower than the same time last year.
• Water storages for Adelaide and Perth are below 40% full.

Low streamflow in western and southern Australia

Lower than average streamflow (based on records since 1975) was observed in May at 29% of the 876 sites nationally with available data. These were observed in:

• the south-west of Western Australia (72% of 68 sites)
• the South Australian Gulf drainage division (80% of 10 sites)
• western and central east of the South East Coast, Victoria drainage division (56% of 92 sites)
• across Tasmania (100% of 22 sites).
• some sites in the north-east and most in the south of the Murray–Darling Basin drainage division (31% of the 338 sites)
• across the Pilbara–Gascoyne (62% of 13 sites).

These were mostly associated with below average rainfall or dry catchment conditions. Very much below average streamflow (lowest 10% of years since 1975) was observed at 14% of sites, in:

• western and central east of Victoria, and north and east of Tasmania
• south-east of the Murray–Darling Basin, and South Australian Gulf drainage division
• the south-west of Western Australia.

May streamflow was average at 28% of sites, spread across Australia. Higher than average streamflow was observed at 43% of sites, including 13% of sites with very much above average streamflow (highest 10% of years since 1975), including:

• across the Queensland North East Coast drainage division
• across the Carpentaria Coast drainage division
• across the Lake Eyre Basin drainage division
• some sites in the Tanami-Timor Sea Coast drainage division
• across the South East Coast, NSW drainage division
• north and north-east and a few sites in south of the Murray–Darling Basin
• in the eastern Victoria.

This was due to significant rainfall events in the north and along the east coast and high soil moisture and runoff in those catchments.

Low storage levels in the west of Western Australia, southern Australia, Murray–Darling Basin and central Queensland

By the end of May, the total water storage in Australia (across 306 public storages) was at 65.2% of capacity, almost the same as the previous month and 9.8% lower than at the same time last year. Storage volumes decreased in May for 171 public storages and were relatively low in several regions including:

• the southern and eastern Murray–Darling Basin
• Victoria
• the South Australian Gulf drainage division
• central Tasmania
• central eastern Queensland
• Harding in Pilbara-Gascoyne drainage division
• Perth and Adelaide urban areas.

Storage volume decreases were generally in regions that had dry catchment conditions and low inflows during the month.

Central Queensland

Storage volume decreased in May for many central Queensland storages such as Fairbairn and Lake Awoonga. The overall storage volume in the Nogoa-Mackenzie system, an important rural water supply for central Queensland communities, was 24.7% full at the end of May a decrease by 0.9% from April and 14.0% from the same time last year. The water storage in Fairbairn was at 22.8% of capacity at the end of May, a 0.9% decrease from April and a 14.6% decrease from the same time last year.

Southern and south-eastern storages

There has been a continued decline in storage levels in May for many storages in southern Australia, such as the Hume dam and in the Wimmera-Mallee. With significant rainfall events in the north and along the east coast and with wet catchment conditions in the northern Basin, the storage volume in May slightly increased across the northern and southern Murray–Darling Basin. Combined storages in the Murray–Darling Basin were 58.0% full at the end of May, a 3.1% increase from April but an 18.2% decrease from the same time last year. Menindee Lakes, in the west of New South Wales was 57.8% full at the end of May, an increase of 32.3% from April and a 1.1% increase from the same time last year.

Water storage in Hume dam, on the Murray River was at 27.8% of capacity at the end of May, a 3.0% increase from April and a 33.9% decrease from the same time last year. In the Wimmera–Mallee system, a critical rural water supply to western Victoria for both domestic and agricultural purposes, storages were 35.4% full at the end of May, a 1.4% decrease from April and an 18.6% decrease from the same time last year.

Water storage in Great Lake in central-northern Tasmania, the second largest by capacity in the state, was 27.6% full at the end of the month, a 0.5% decrease from April and an increase of 7.3% from the same time last year.

Urban storages

At the end of May, the surface water storages supplying most capital cities were high (over 73% of their accessible capacity), with the exception of storages supplying Adelaide and Perth, which are below half capacity following an extended period of severe rainfall deficiencies. Perth's surface water storages were 36.1% full at the end of May, a 0.8% decrease from April, and a 0.4% decrease from the same time last year. Adelaide's surface water storages were 34.3% full at the end of May, a 1.2% decrease from April, and a 8.3% decrease from the same time last year. The Harding storage in the Pilbara–Gascoyne drainage division was at 23.8% of capacity at the end of May, a 2.8% decrease from April and a 7.2% decrease from the same time last year.

The long-term decline in surface water inflows to Perth's storages, as a consequence of reduced rainfall due to climate change, means the city's water supply is reliant on desalination and groundwater. Adelaide's water supply requirements are augmented by alternative sources. This is mostly by water transfer from the River Murray, and with some supply from desalination and groundwater. In South Australia, pipelines from the River Murray also augment water supply for the Eyre and Yorke Peninsulas and some of the south-east of the state. In response to developing rainfall deficiencies, the Victorian desalination plant commenced buffering surface water storage used for Melbourne and Geelong.