Drought

Rainfall deficiencies persist in Western Australia, South Australia, Tasmania and eastern Victoria

Rainfall in July was below average over much of the southern half of mainland Australia away from the southern coastal fringe and southern alpine areas, although most areas were less anomalously dry than they had been in June. Rainfall was very much below average (the lowest 10% on record) across much of the same area with some small patches of lowest on record.

After the exceptionally dry June across Australia (the second-driest June on record for the country as a whole) and below average July rainfall, the first half of the southern wet season (April to November) has been very dry over large parts of eastern and southwestern Australia. Western Australia has a larger spatial area of very much below average rainfall at this April to July period than at the five-month March to July drought period. Areas that received above average rainfall in March are not showing up on the five-month drought map but are dry over the April to July period. These areas include large parts of New South Wales (25% of the State) which are showing up as very much below average for the April to July period. Shorter standard periods are also showing very much below average rainfall with areas of lowest on record at some periods, these will monitored closely for any further developments.

5-month rainfall deficiencies

Compared to the 4-month period ending June 2017, rainfall deficiencies have increased slightly in both areal extent and severity along the west coast of Western Australia, with a large area around and south of the Gascoyne coast observing lowest on record rainfall compared to similar March to July periods.

Rainfall deficiencies persist on the Eyre Peninsula in South Australia, along with the Yorke and Fleurieu peninsulas, parts of the Adelaide region and the mid-North, and on Kangaroo Island. Deficiencies also persist in West Gippsland and adjacent parts of northeastern Victoria. In Tasmania, deficiencies have decreased in spatial extent but increased slightly in severity.

Rainfall deficiencies have decreased markedly across the southern half of the NT into western Queensland following a wet July in these areas. This is a seasonally dry time of year across the region and even small rainfall totals can impact on rainfall deficiencies.

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Soil moisture

Daytime temperatures were warmer than average over large parts of the country in June and July. The clear skies and the dry, warm air have led to unusually high evaporation rates for winter in many areas, contributing to below average soil moisture in these regions.

Soil moisture in the lower layer (from 10 cm to 100 cm deep) decreased for July compared to June across most of southern Australia inland from the coastal strip and alpine areas. The only areas to observe significant increases in lower layer soil moisture during the month were through southwest Western Australia, parts of south-coastal South Australia and western Tasmania although soil moisture in these regions generally still remains below levels expected for this time of year.

Soil moisture for July was below average for the west and south of Western Australia; most of southern South Australia, except the far southeast; areas of eastern Tasmania; eastern Victoria; areas of inland eastern and northern New South Wales; and much of central Queensland.

  • July rainfall below average for much of southern Australia
  • Serious to severe rainfall deficiencies are present at the 5-month timescale near the west coast of Western Australia, between the Eyre Peninsula and Adelaide region in South Australia, in western and southern Tasmania, and in West Gippsland in Victoria
  • Soil moisture is below average across the west and south of Western Australia, most of southern South Australia, inland New South Wales, eastern Victoria, and parts of Tasmania

Product code: IDCKGD0AR0


Soil moisture data is from the Bureau's Australian Water Resources Assessment Landscape (AWRA-L) model, developed through the Water Information Research and Development Alliance between the Bureau and CSIRO.
See: Australian Landscape Water Balance.

This section displays rainfall maps. Current drought status is described in the previous section. For historical drought status statements, go to archive of drought statements

Also available at Maps – recent conditions

What is drought?

Drought is a prolonged, abnormally dry period when the amount of available water is insufficient to meet our normal use. Drought is not simply low rainfall; if it was, much of inland Australia would be in almost perpetual drought. Because people use water in so many different ways, there is no universal definition of drought. Meteorologists monitor the extent and severity of drought in terms of rainfall deficiencies. Agriculturalists rate the impact on primary industries, hydrologists compare ground water levels, and sociologists define it by social expectations and perceptions.

It is generally difficult to compare one drought to another, since each drought differs in the seasonality, location, spatial extent and duration of the associated rainfall deficiencies. Additionally, each drought is accompanied by varying temperatures and soil moisture deficits.

Rainfall averages, variability and trends

Median rainfall map, links to climate average maps An area experiences a rainfall deficit when the total rain received is less than the average rainfall for that period.

Definitions

Definitions

Lowest on record - lowest since at least 1900 when the data analysed begin.
Severe deficiency - rainfalls in the lowest 5% of historical totals.
Serious deficiency - rainfalls in the lowest 10% of historical totals, but not in the lowest 5%.

Very much below average - rainfalls in the lowest 10% of historical totals.
Below average - rainfalls in the lowest 30% of historical totals, but not in the lowest 10%.
Average - rainfalls in the middle 40% of historical totals.
Above average - rainfalls in the highest 30% of historical totals, but not in the highest 10%.
Very much above average - rainfalls in the highest 10% of historical totals.

Australian Government drought assistance

Department of Agriculture and Water Resources information and contacts: