Friday 1 September 2017 — Seasonal Climate Summary for Australia — Product Code IDCKGC1A00

Australia in winter 2017

Temperatures Rainfall Extremes Important notes the top

In Brief

• Overall, winter national mean temperature very much above average; fifth-warmest on record for winter
• Exceptionally warm winter daytime temperatures for Australia
• Mean maximum temperature warmest on record nationally, and for Queensland, Western Australia, and the Northern Territory; second-highest for South Australia, and third-highest for New South Wales
• Mean minimum temperatures above average nationally, but cooler than average in the southeast, particularly during June
• Rainfall very much below average overall; ninth-driest winter on record nationally, tenth-driest for New South Wales and eleventh-driest for Western Australia
• June particularly was very dry for the southeast; record low rainfall for Victoria, and second-driest on record nationally

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Temperatures

The winter mean temperature was very much above average for Australia, placing at fifth-warmest on record with an anomaly of +1.11 °C. Mean temperatures were the second-warmest on record for winter for Queensland, third-warmest for Western Australia, and ninth-warmest for the Northern Territory.

Mean maximum temperatures were the highest on record (+1.90 °C) for Australia as a whole. Daytime temperatures averaged across winter were above average for nearly all of Australia, with more than 90% of Australia in the highest 10% of historical observations (decile 10). Large areas of northern Australia observed record high mean maxima; for Queensland, Western Australia, and the Northern Territory winter mean maxima were the warmest on record, while winter days were the second-warmest on record for South Australia and third-warmest on record for New South Wales.

Daytime temperatures were above average for most of Australia during each month on winter. June was particularly warm for the southwest, and the third-warmest June on record for Western Australia as a whole. July and August were both particularly warm for northern Australia, and record warm for large areas of the north in July in part due to a heat event late in the month which saw record high July daily temperatures in Western Australia, South Australia, Victoria and New South Wales. For Australia as a whole July mean maxima were the warmest on record. August heat saw a handful of records set for high August temperatures, or warmest temperature so early in the season, at some sites in South Australia and western New South Wales around the middle of the month, and in Western Australia during late August.

Mean minimum temperatures were above to very much above average for most of Queensland and the northern half of the Northern Territory, and areas of Western Australia, mostly in the interior and southwest. Minimum temperatures were below to very much below average for large areas of southeastern Australia, with winter nights the coldest since 1997 for the region. Minimum temperatures were also cooler than average for an area of southeastern Western Australia, and an area spanning the Western Australia–Northern Territory border.

During June, persistent high pressure systems brought long strings of clear, cold nights, keeping mean minima in the lowest 10% of historical observations (decile 1) for the month across much of the southern mainland, and record low for some parts of southern inland New South Wales and northern Victoria. A cold outbreak during the first few days of July saw a number of stations in southern New South Wales and Victoria observe their coldest nights on record.

Aside from the exceptional persistent high pressure anomalies to the south of Australia during June, abnormally high maximum temperatures throughout the rest of winter occurred in the absence of Australia's most important large-scale climate drivers; both the El Niño–Southern Oscillation and the Indian Ocean Dipole were both neutral. Winter climate was however influenced by secondary climate drivers including warmer than average sea surface temperatures to the north and east of Australia, below average rainfall (resulting in lower than average soil moisture, and increased numbers of sunny days), and the long-term increasing trend in global air and ocean temperatures.

Areal average temperatures
	Maximum Temperature			Minimum Temperature			Mean Temperature
	Rank (of 108)	Anomaly (°C)	Comment	Rank (of 108)	Anomaly (°C)	Comment	Rank (of 108)	Anomaly (°C)	Comment
Australia	108	+1.90	highest (was +1.60 °C in 2009)	= 70	+0.31		104	+1.11	5th highest
Queensland	108	+2.23	highest (was +2.22 °C in 2009)	93	+1.08		107	+1.66	2nd highest (record +1.97 °C in 1973)
New South Wales	106	+1.59	3rd highest (record +1.95 °C in 2002)	27	−0.46		= 89	+0.56
Victoria	87	+0.50		14	−0.65		= 47	−0.07
Tasmania	= 68	+0.08		17	−0.46		37	−0.18
South Australia	107	+1.70	2nd highest (record +1.75 °C in 2002)	34	−0.23		98	+0.74
Western Australia	108	+1.99	highest (was +1.56 °C in 2002)	= 78	+0.30		106	+1.14	3rd highest (record +1.41 °C in 1996)
Northern Territory	108	+1.99	highest (was +1.95 °C in 1996)	75	+0.44		100	+1.22	9th highest

Rank ranges from 1 (lowest) to 108 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Anomaly is the departure from the long-term (1961–1990) average.

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

Temperatures Rainfall Extremes Important notes the top

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Rainfall

Winter rainfall was the ninth-lowest on record for Australia nationally, and lowest since 2002. Rainfall for New South Wales and Western Australia were also the tenth- and eleventh-lowest on record for the season, respectively.

Rainfall for the season was below to very much below average for most of Western Australia, most of southern South Australia, the western and southern Top End in the Northern Territory, and most of the eastern States. Winter rainfall was generally closer to average in inland southeastern Western Australia, central northern South Australia, northwestern Queensland and much of the Cape York Peninsula. Above average rainfall was restricted to an area of the central Northern Territory, where an out-of-season rainfall event during the second week of July brought totals in excess of 25 mm over a broad area during what is typically the dry season.

June was a very dry month for the southeast of Australia and areas across the west of Western Australia. It was the second-driest June on record for the country nationally, and driest on record for Victoria. More than 100 stations with more than 50 years of observations have reported their lowest June rainfall total on record, mostly within the Murray-Darling Basin. This very dry start to winter was largely due to higher than average mean sea level pressure (MSLP) patterns across southern Australia. The subtropical ridge was both stronger, and further south, than usual for this time of year, and the Southern Annular Mode (SAM) was in a positive phase, leading to fewer rain-bearing low pressure systems and cold fronts affecting southern Australia and reducing cloudiness over land.

July was also drier than average across large parts of southern Australia. August saw a return to more average patterns, with some parts of the south of Western Australia, southeastern South Australia, and western and northern Victoria even receiving above average rainfall, although it rainfall for the month was very much below average for coastal northeastern New South Wales and parts of adjacent southeastern Queensland.

Area-average rainfall
	Rank (of 118)	Average (mm)	Departure from mean	Comment
Australia	9	36.7	−43%	9th lowest; lowest since 2002
Queensland	17	19.4	−62%
New South Wales	10	58.8	−49%	10th lowest; lowest since 2002
Victoria	18	149.3	−27%
Tasmania	25	363.8	−17%
South Australia	23	34.9	−37%
Western Australia	11	34.9	−43%
Northern Territory	73	15.0	−17%
Murray-Darling Basin	9	56.7	−49%	9th lowest; lowest since 2002

Rank ranges from 1 (lowest) to 118 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Departure from mean is relative to the long-term (1961–1990) average.

Rainfall maps
	Totals	Percentages	Deciles
Total rainfall

Temperatures Rainfall Extremes Important notes the top

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Australian weather extremes in winter 2017
Hottest day	39.6 °C	at Mandora (WA) on 24 August
Coldest day	−5.4 °C	at Mount Hotham (Vic) on 27 August
Coldest night	−12.1 °C	at Perisher Valley AWS (NSW) on 16 July
Warmest night	26.6 °C	at Coconut Island (Qld) on 2 June
Wettest day	145.6 mm	at Perisher Valley AWS (NSW) on 16 August

Temperatures Rainfall Extremes Important notes the top

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