Rainfall deficiencies

A mob of sheep raises dust north of Dubbo, New South Wales, during drought. Photo by Department of Foreign Affairs and Trade Australia is a large continent containing many different climate zones, from wet tropics in the north, arid and semi-arid conditions in the interior, and alpine climates in the south-east. Each climate zone is influenced by very different large-scale, predominant weather and climate patterns. For this reason, at any time different parts of the Australian continent can be affected by very different climate extremes. An example of this occurred in 2010, where southwest Western Australia experienced its driest year on record, in contrast to the rest of Australia, which received above-average to very-much-above-average rainfall.

Use our Drought Statement, rainfall maps and reports to watch for areas with significant long and short-term rainfall deficiencies.

Issued on 3 December 2014

Rainfall deficiencies generally increase across eastern Australia

November rainfall was below to very much below average for eastern Australia and much of the Top End. Monthly rainfall was in the lowest ten per cent of records (decile 1) for most of northern Tasmania and most of the Cape York Peninsula in Queensland, as well as other scattered areas in the east and centre of Queensland and New South Wales. Rainfall has been below average across large parts of eastern Australia for most of 2014; rainfall deficiencies across parts of the east have been exacerbated by particularly dry conditions during the past two months. Overall, rainfall during the second half of the southern growing season (July to November) has been below to very much below average across most of southeast Australia, coinciding with record-warm temperatures.

5-month rainfall deficiencies

For the 5-month period (July–November 2014), below-average November rainfall across much of eastern Australia has increased the area of serious and severe rainfall deficiencies along and inland of the Great Dividing Range in New South Wales extending into southeastern Queensland, across the central and southern Cape York Peninsula in Queensland and also in northwestern Tasmania. Serious and severe deficiencies also persist across the agricultural region of South Australia and the western half of Victoria, southern New South Wales, the Top End and scattered areas around central Australia, although rainfall in the past month has reduced or alleviated deficiencies north of Carnarvon and near Giles in Western Australia, in the northwest and east of the Northern Territory and across western Queensland.

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12-month rainfall deficiencies

The extent of rainfall deficiencies in eastern Australia has also increased at the 12-month scale (December 2013 – November 2014). Deficiencies are in place over much of western Victoria and adjacent southeastern South Australia, along the east coast of Tasmania and in smaller areas of the west coast, and in a broad area of northeastern New South Wales and southeastern Queensland where the area affected by severe deficiencies (lowest 5% of records) has also increased. Scattered pockets of serious deficiencies (lowest 10% of records) also remain between northeastern South Australia and Queensland's tropical coast, and in the central Top End, southwest of the Northern Territory and on Western Australia's west coast.

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26-month rainfall deficiencies

At the 26-month (November 2012 – November 2014) timescale, serious and severe rainfall deficiencies persist across much of Queensland away from the eastern coast, extending into inland northeastern New South Wales, the southwest of the Northern Territory and northeast South Australia. Rainfall in the past month has slightly decreased deficiencies around the western border of Queensland while deficiencies in the remainder of this area have generally increased slightly.

Serious and severe deficiencies have also slightly increased where they persist over most of the western half of Victoria, excluding the area immediately along the coast and New South Wales border, adjacent parts of southeastern South Australia, and in an area of the southern coastal Gascoyne around Shark Bay in Western Australia.

November typically sees the start of moderate rainfall totals occurring along the east coast of Queensland as the northern wet season develops; a late start to the wet season this year would make removal of these longer-term deficiencies in Queensland less likely as they are largely the result of below-average rainfall over the two preceding wet seasons. The northern wet season spans October–April; rainfall will have to be above average over much of the remaining months to April to lift these areas out of deficiency, i.e. above the tenth percentile.

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Soil moisture

Upper layer weekly soil moisture for the week ending 30 November was very much below average across the Top End, eastern Queensland, most of New South Wales, parts of eastern Victoria and from western Victoria through coastal South Australia, and also across northern and eastern Tasmania and in small areas along the west coast of Western Australia. Following recent rainfall upper layer soil moisture is above average across much of northwest Australia, extending through Western Australia from the Pilbara to the south coast, and is also above average for smaller areas south of the Gulf of Carpentaria, in western Queensland and the south of the Northern Territory, and through southern New South Wales and adjacent South Australia.

Compared to last month, lower layer weekly soil moisture for the week ending 30 November has decreased across eastern Australia, the far north and the southwest. Lower layer soil moisture is below average across parts of central and a large area focused on southeastern Queensland and the northeastern half of New South Wales, extending along the Great Dividing Range and parts of southern New South Wales across much of northeastern Victoria then across the western half of Victoria and adjacent southeastern South Australia. Soil moisture is also below average for most of northern and eastern Tasmania, along the west coast of Western Australia and through the central Top End. Soil moisture remains above average in the eastern central Cape York Peninsula, central Northern Territory and much of the eastern half of Western Australia as well as in parts of coastal South Australia, mostly in the west.

Further information

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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

These maps are also available from Maps - recent conditions

Weekly rainfall updates

Current map, small viewThe Weekly Rainfall Update describes rainfall over the previous week. It includes a map and a summary table of the highest weekly totals. A discussion of the impact of recent rains on rainfall deficiencies is also presented.

Rainfall and temperature outlooks

Current map, small viewRainfall and temperature outlooks outline likely conditions over three-month periods. Outlooks are available for single months, three months, and for any location in Australia. Formats include text summaries, maps, graphs and video.
Rainfall and temperature outlooks: Outlooks
Previous outlooks: Archive of outlooks Archive of outlook maps

Seasonal streamflow forecasts

Australian streamflows are among the most variable in the world. Seasonal streamflow forecasts extends water management decision making capability. Forecasts are issued monthly.

Climate statements archive

The archive includes previous monthly, seasonal and annual climate summaries for nation-wide, state/territory and capital city conditions.

Maps of recent conditions

CSIRO water balance maps

Small image of water balance mapCSIRO (AWAP) Water balance maps include maps of soil moisture and water fluxes contributing to changes in soil moisture (rainfall, transpiration, soil evaporation, surface runoff and deep drainage).

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.

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

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.

Acknowledgements

Front page photo, provided by Department of Foreign Affairs and Trade: 'A mob of sheep raises dust north of Dubbo, New South Wales, during drought'