Friday, 1 March, 2013 — Seasonal Climate Summary for Australia — Product Code IDCKGC2A00

Australia in summer 2012–13

Temperatures Rainfall Extremes Important notes the top

In Brief

In terms of both maximum and mean temperatures, summer 2012–13 was the warmest on record for Australia. Minimum temperatures were also significantly above average for the season, placing as the sixth warmest in 103 years of record. All mainland States and Territories recorded maxima in the top 10 records for summer; only a strip of the east coast and part of Western Australia recorded near-average maxima, associated with above-average rainfall. Minima were also generally above to very much above average, with scattered areas across the tropics and part of South Australia recording near-average minima.

Summer rainfall was below average for most of Australia, except for most of Western Australia and a strip extending along the east coast and adjacent hinterland from Mackay to southern New South Wales. Across this part of eastern Australia rainfall was above average, and generally in the highest decile closer to the coast. Rainfall was also above average in western and northern Western Australia, excluding the far north. The remainder of Western Australia and the central Northern Territory recorded near-average summer rainfall.

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Temperatures

For Australia as a whole, summer maximum temperatures were 1.44 °C above average, making this the hottest summer in Australia since records commenced in 1910, and surpassing the previous record (held by summer 1982–83) by a large margin (0.21 °C). All States recorded maxima at least 0.95 °C warmer than average; South Australia recorded the largest anomaly at +1.98 °C. All mainland States placed in the ten highest records for summer maxima.

A small area of the Pilbara recorded below average summer maxima, but for the remainder of the country maxima were generally above to very much above average. 62 per cent of Australia recorded maxima in the highest 10 per cent of records, and for 6 per cent of Australia summer was the hottest on record — record high maxima were recorded in parts of the far north, coastal Western Australia and central Australia. A large area of the inland of the eastern States and smaller parts of the far north, centre, and southern Western Australia recorded maxima 2 to 3 °C above average for summer.

Australia has been experiencing warmer-than-average temperatures since spring last year with a number of heatwaves recorded over the period and numerous locations setting daytime records for maximum temperature throughout spring and summer. The exceptionally long and widespread heatwave in late December and the first half of January (see the Special Climate Statement) contributed to making January the hottest month ever recorded in Australia (records commenced in 1910). Although few individual locations recorded their warmest summer on record, the extent of the heat across the continent has been unprecedented; usually extreme heat will be confined to a smaller geographic area for a shorter length of time than has been the case this season. December and January showed consistently above-average maxima across the majority of Australia while February was below average on the central east coast, associated with significant rainfall.

Minima were similarly elevated across Australia during summer, but to a lesser degree than maxima. For Australia as a whole, minimum temperatures were 0.79 °C above average, ranking as the sixth warmest summer on record. All States recorded minima well above average (ranging from +0.48 °C in Tasmania to +1.31 °C in New South Wales) but only Western Australia ranked in the top 5 records for the season (5th).

Summer minima were above average across most of Australia and in the highest 10 per cent of records for most of the west, centre, and north. Scattered areas across the tropical north recorded average minima with a few small areas recording below-average night-time temperatures. 41 per cent of Australia recorded minima in the highest 10 per cent of records and 2 per cent of the country, mostly in the Pilbara and western central Australia, recorded its highest summer minima. Small areas of the arid interior of Australia were 2 to 3 °C warmer than average in terms of minima. January nights were warm nearly everywhere, while December was cooler than average across parts of the north, and February cool for southeast Queensland and warmer than average for the south and north, and most of Western Australia.

Areal average temperatures
	Maximum Temperature			Minimum Temperature
	Rank (out of 103)	Anomaly* (°C)	Comment	Rank (out of 103)	Anomaly* (°C)	Comment
Australia	103	+1.44	highest; previous record +1.23 (1982–83)	98	+0.79	sixth highest; record is +0.94 (1972–73)
Queensland	100	+1.58	fourth highest; record is +2.96 (1938–39)	93	+0.61
New South Wales	97	+1.91	seventh highest; record is +2.25 (2005–06)	95	+1.31
Victoria	100	+1.77	fourth highest; record is +2.50 (2000–01)	88.5	+0.90
Tasmania	90	+1.06		83.5	+0.48
South Australia	102	+1.98	second highest; record is +2.72 (2000–01)	90	+0.96
Western Australia	94	+0.95	tenth highest; record is +1.72 (1997–98)	99	+0.78	fifth highest; record is +0.98 (2009–10)
Northern Territory	102	+1.44	second highest; record is +1.52 (1985–86)	94.5	+0.58

^*Anomaly is the departure from the long-term (1961–1990) average.
A fractional rank indicates that the value is tied for that rank.

Temperature maps
	Mean	Anomaly	Deciles
Mean daily maximum temperatures
Mean daily minimum temperatures

Temperatures Rainfall Extremes Important notes the top

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Rainfall

Rainfall for summer 2012–13 was generally below average across Tasmania and the majority of the mainland, excluding the eastern seaboard of both New South Wales and southern Queensland. Western Australia west of a line from the extreme northeast to Albany generally received above-average rainfall except for the Kimberley, which, along with the remainder of the State and the central Northern Territory, recorded neawr-average rainfall. A large part of eastern Australia covering roughly from Mackay to Wollongong and extending inland to Goondiwindi recorded above-average summer rainfall, with much of the area within about 200 km of the coast in the highest decile. A large part of the Pilbara and adjacent parts of the Interior of Western Australia also recorded rainfall in the highest decile.

Area-averaged rainfall for Australia was 175.1 mm (16 per cent below average), ranking as the 29th driest summer in the 113 years since records commenced. Western Australia was the only State to record above-average rainfall for the season (15 per cent above the long-term mean); much of the west of Australia has received above-average rainfall in most or all months since October 2012. South Australia was the State to record the most significant departure from average totals, at 58 per cent below average (18th driest summer on record). Queensland, Tasmania, Victoria and the Northern Territory also ranked in the lower end of totals, with South Australia, Victoria and the Northern Territory recording their driest summers for more than 20 years. New South Wales placed at 61st driest, near the median. In total, 9 per cent of the country fell into the lowest decile (lowest 10 per cent of totals in the historical record) for summer as a whole.

The rainfall deficits in the southeast were mostly a result of very low January rainfall; for Victoria it was the 7th driest January on record with the monthly total 79 per cent below average, while South Australia recorded an even drier month with a total 88 per cent below average. The high totals along the eastern coast were also largely a result of January rainfall, primarily associated with the passage of ex-tropical cyclone Oswald across the Cape York Peninsula and southwards along the east coast from mid-month (see the Special Climate Statement for details of associated flooding and storm damage). The remnants eventually dissipated near Sydney on 29 January. There were also substantial rains across much of this region in late February with February rainfall generally below average across the north and southwest, and above average in northwest Western Australia and the southeast mainland. December was generally dry across the eastern States and wet in the far west, again owing mostly to a single event which saw daily rainfall records set in parts of the southwest (see the Special Climate Statement).

Area-average rainfall
	Rank (out of 113)	Average (mm)	Departure from mean*	Comment
Australia	29	175.1	−16%
Queensland	26	255.2	−21%
New South Wales	61	158.5	−7%
Victoria	22	80.8	−32%	lowest since 1984–85
Tasmania	20	184.2	−24%
South Australia	18	25.9	−58%	lowest since 1985–86
Western Australia	84	171.3	+15%
Northern Territory	15	215.5	−32%	lowest since 1991–92
Murray-Darling Basin	32	106.5	−26%

^*The mean is calculated for the 1961–1990 reference period.

Rainfall maps
	Totals	Percentages	Deciles
Total rainfall

Temperatures Rainfall Extremes Important notes the top

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Australian weather extremes in summer 2012–13
Hottest day	49.6 °C at Moomba Airport (SA) on 12 January
Coldest day	−0.2 °C at Mount Baw Baw (Vic.) on 4 December
Coldest night	−5.3 °C at Perisher Valley AWS (NSW) on 10 December
Warmest night	33.5 °C at Wiluna (WA) on 9 January
Wettest day	653.0 mm at Numinbah (Qld.) on 28 January

Temperatures Rainfall Extremes Important notes the top

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Further information

National Climate Centre
Bureau of Meteorology
Phone (03) 9669 4082
Email Helpdesk.Climate@bom.gov.au

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