Friday 1 June 2018 — Seasonal Climate Summary for Australia — Product Code IDCKGC1A00

Australia in autumn 2018

Temperatures Rainfall Extremes Important notes the top

In Brief

• An exceptionally warm autumn for Australia; nationally the fourth-warmest autumn on record
• Maxima and minima both above average, and days exceptionally warm for large areas and for Australia as a whole
• National monthly mean maximum temperature for autumn fourth-warmest on record for autumn
• Only Queensland, the Northern Territory, and Tasmania rank outside the top ten for autumn mean maximum temperature
• Autumn rainfall totals were below average for most of Australia, and very much below average across the southern mainland
• Rainfall was above average between the southeast of the Northern Territory and Queensland's North Tropical Coast, due to above to very much above average rainfall during March

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Temperatures

Autumn was exceptionally warm for Australia. All regions except Tasmania, Queensland, and the Northern Territory observed mean temperatures for the season amongst the ten warmest on record, and for Australia as a whole it was the fourth-warmest autumn on record (1.18 °C above the long-term average). Both maximum and minimum temperatures were warmer than average for Australia, particularly maxima, which were the fourth-warmest on record for autumn (+1.74 °C). Minima ranked just outside the top ten, at 0.62 °C above the long-term average

Daytime temperatures for autumn were above average for nearly all of Australia, in the highest 10% of historical observations (decile 10) for most areas except for Tasmania and for Queensland away from the southern border. Mean monthly maxima were the warmest on record for much of New South Wales, including Sydney; parts of Victoria, particularly far eastern Victoria; and about Northwestern Cape in Western Australia.

Mean minimum temperatures were above to very much above average for the majority of Australia. Minima were below average for most of the Kimberley in Western Australia and the southeastern Top End in the Northern Territory. Minima were near average for much of the remainder of the northeastern quarter of Western Australia, the southwest of the Northern Territory, parts of Queensland's east and Gulf Country, along the border of New South Wales and Victoria inland of the Great Dividing Range, and in areas along the south coast of Western Australia.

Each of the individual months of autumn was warmer than average nationally, although heavy rain and associated cloud cover led to below average maxima for March over much of northern Queensland, and mean monthly minima were cooler than average for a large area stretching from the Kimberley in Western Australia, through the south of the Northern Territory, into pastoral South Australia. April was an exceptionally warm month, with persistent abnormal warmth setting records for intensity, persistence, or both. Records set are discussed in a Special Climate Statement Persistent summer-like heat sets many April records.

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

Autumn rainfall was below to very much below average for most of Australia. Rainfall for the season was in the lowest 10% of historical observations (decile 1) for much of the southern mainland; for southern Australia as a whole, autumn rainfall was the second-lowest on record. New South Wales, South Australia, and Western Australia all observed area-averaged autumn rainfall amongst the ten lowest on record for their respective States, with a number of stations in New South Wales and Western Australia receiving record-low rainfall for the season.

Rainfall was below average for most of the southern mainland in each month of autumn. April was the eighth-driest on record nationally, and May was the third-driest on record. A number of stations in Victoria, and New South Wales observed record-low monthly rainfall totals for April, followed by more record-low rainfall totals for May in New South Wales.

There is a consistency between low rainfall this autumn for southern Australia and climate change.

March rainfall was above to very much above average for much of the south of the Northern Territory, and western, central, and much of northern Queensland. Rain in these regions was largely the result of a tropical low in early March, and tropical cyclone Nora late in the month; some daily rainfall records were set in Queensland associated with each of these events. Tropical cyclone Marcus also affected the Top End and Western Australia during March, becoming the most intense tropical cyclone in the Australian region for more than a decade.

Southeastern Tasmania observed above average May rainfall, largely as a result of a single event when a complex low pressure system brought record-breaking rain overnight from the 10th to 11th, with significant flooding around Hobart.

Area-average rainfall
	Rank (of 119)	Average (mm)	Departure from mean	Comment
Australia	20	80.9	−33%
Queensland	88	174.2	+7%
New South Wales	8	56.5	−60%	8th lowest; lowest since 2005
Victoria	15	95.3	−39%
Tasmania	84	365.2	+7%
South Australia	11	19.3	−66%
Western Australia	7	34.3	−62%	7th lowest; lowest since 1994
Northern Territory	40	91.8	−34%
Murray-Darling Basin	8	47.4	−60%	8th lowest

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 in autumn 2018
Hottest day	45.9 °C	at Roebourne Aero (WA) on the 28th and Mardie (WA) on 29 March
Coldest day	−2.6 °C	at Mount Hotham (Vic.) on 10 May
Coldest night	−6.7 °C	at Perisher Valley AWS (NSW.) on 25 May and Glen Innes Airport AWS (NSW) on the 31st
Warmest night	31.7 °C	at Wittenoom (WA) on 28 March
Wettest day	593.0 mm	at Port Douglas - Warner St (Qld) on 26 March

Temperatures Rainfall Extremes Important notes the top

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