Friday 1 June 2018 — Monthly Summary for Australia — Product Code IDCKGC1A00

Australia in May 2018

Temperatures Rainfall Extremes Important notes the top

In brief

• On average, days much warmer than average for Australia during May, and nights cooler than average
• National monthly mean temperature for May somewhat above average
• The third-driest May on record for Australia, with rainfall for the month below average across most of Australia except parts of the southeast
• Strong cold front on the 10th brought severe winds, heavy rain, and flooding to southeast Tasmania, including Hobart

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Temperatures

May was warmer than average for Australia as a whole; the national monthly mean temperature was 0.19 °C above average.

Maximum temperatures were particularly warm, with a national anomaly of +0.86 °C. Mean monthly maximum temperatures were above average for most of Australia, and in decile 10 (the warmest 10% of historical observations) for May along the west coast of Western Australia and across most of eastern New South Wales, extending into eastern Victoria and southeast Queensland, as well as for an area of the coastal Top End. Maxima were near average for South Australia, western and Gulf Country Queensland, and an area of northwestern Australia spanning the eastern Kimberley and Victoria River District in the Northern Territory.

The national mean minimum temperature was cooler than average at 0.49 °C below average for May. Minimum temperatures for the month were above average across Tasmania, southeastern South Australia, most of Victoria away from the Murray River, and across the Cape York Peninsula in Queensland. Minima were cooler than average for large areas of northern and central Western Australia and areas of that State's southern coast, for the south of the Northern Territory and the southeastern Top End, and for much of pastoral South Australia.

Abnormal warmth had dominated April, and persisted through much of May, aided by large positive surface pressure anomalies over the Great Australian Bight. With high pressure dominating the weather, it was windier than average in Tasmania and southern Victoria. The first week of the month was particularly warm, with a number of stations in Victoria, and New South Wales observing their warmest May day on record on the 3rd.

The passage of a strong cold front brought stormy weather and low temperatures to the southeast, with snow across the Alpine area and a maximum temperature of 12.8 °C on the 10th in Melbourne, which was that city's coldest day so early in the season since 1970. The cold outbreak even reached into the north of the country, with a southeast surge over the Top End dropping the minimum temperature at Darwin Airport below 20 for several days.

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

May was an exceptionally dry month for Australia; nationally, May rainfall was the third-lowest on record and lowest for May since 2008 (2008 was Australia's driest May on record). Monthly total rainfall was below average for most of Australia, and in the lowest 10% of historical observations (decile 1) for May for large areas of southern Western Australia, northern and eastern New South Wales, and southern Queensland. For New South Wales as a whole May was the seventh-driest on record, while for the Northern Territory it was the ninth-driest on record.

A large number of stations in New South Wales received record low May rainfall or their lowest May rainfall for at least 20 years.

Only a few small areas received above average rainfall for the month, in southwestern and parts of southern Victoria and in parts of western, central, and southeastern Tasmania.

A large amount of this rain fell in a single event, when a complex low pressure system and strong cold front crossed Tasmania on the 10th. Record-breaking rain fell in southeastern Tasmania overnight from the 10th to 11th, particularly around Hobart, where significant flooding resulted.

Area-average rainfall
	Rank (of 119)	Average (mm)	Departure from mean	Comment
Australia	3	8.7	−69%	3rd lowest (record 7.8 mm in 2008)
Queensland	11	5.0	−83%
New South Wales	7	11.6	−75%	7th lowest; lowest since 2006
Victoria	61	58.2	−10%
Tasmania	77	145.5	+6%
South Australia	28	8.9	−58%
Western Australia	11	6.6	−74%
Northern Territory	9	0.4	−97%	9th lowest
Murray-Darling Basin	14	13.7	−68%

Rank ranges from 1 (lowest) to 119 (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 during May 2018
Hottest day	38.3 °C	at Roebourne Aero (WA) on the 10th
Coldest day	−2.6 °C	at Mount Hotham (Vic.) on the 10th
Coldest night	−6.7 °C	at Perisher Valley AWS (NSW.) on the 25th and Glen Innes Airport AWS (NSW) on the 31st
Warmest night	28.5 °C	at Troughton Island (WA) on the 7th
Wettest day	236.2 mm	at kunanyi (Mount Wellington Pinnacle) (Tas.) on the 11th

Temperatures Rainfall Extremes Important notes the top

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