Wednesday 1 November 2017 — Monthly Summary for Australia — Product Code IDCKGC1A00

Australia in October 2017

Temperatures Rainfall Extremes Important notes the top

In brief

• Mean maximum temperature very much above average for the north and southeast Australia
• Mean minimum temperature above average for most of Australia, and warmest on record for southeast Queensland and northeast New South Wales
• For Australia as a whole, mean monthly temperature very much above average: tenth-warmest October on record
• October rainfall above to very much above average over much of Queensland, northern New South Wales, and the north and interior of Western Australia
• Rainfall below average for large areas along the southern coastline and nearly all of Tasmania

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Temperatures

October was another very warm month for Australia, particularly in terms of minimum temperatures (third-warmest October mean minimum temperature on record, 1.51 °C above average). Queensland, New South Wales, and Tasmania also observed mean minima within the top four warmest on record for October.

Minimum temperatures were above average across nearly all of Australia for October. Minima were in the warmest 10% of historical observations (decile 10) for October along the northern coast of Australia from the northeastern Pilbara to the Cape York Peninsula in Queensland and across most of that State, and also across most of New South Wales except for parts of the centre and south, all of Tasmania, the southern coast of Victoria, parts of coastal South Australia, and the far southeast of Western Australia. For much of southeast Queensland and northeastern New South Wales, where above average rainfall was accompanied by cloudy skies, mean monthly minima for October were the highest on record.

Maximum temperatures for October were also above average for Australia as a whole (1.33 °C above average). October maxima were the fourth-warmest on record for Tasmania, and the seventh-warmest for Victoria. Mean monthly maxima were in the highest 10% of historical observations (decile 10) for October across the Kimberley, the north of the Northern Territory, an area of Queensland's Gulf Country, and most of southeast Australia, including Tasmania.

Maxima were however near-average for eastern Queensland except the north of the Cape York Peninsula, adjacent border regions of northern New South Wales, and large areas of Western Australia covering the South West Land Division and adjacent areas further inland, extending into the central Interior. Maxima were also near-average for part of eastern Central Australia.

The warmth across the month was marked by a notable lack of cold outbreaks, rather than exceptional warm spells. One significant cold outbreak at the start of the month did bring very cold nights across much of southern Australia between the 1st and 3rd, with overnight temperatures four to eight degrees cooler than average over large areas.

Frontal systems also assisted in raising temperatures at several points during the month as northerly winds ahead of approaching fronts directed warm air into the south. Between the 15th and 18th a low pressure system resulted in, an area of anomalies in excess of more than 12 degrees above average tracking along the coast of southern Australia as the system moved eastward. Record warm days or nights were observed at a number of stations, with multiple stations setting records for warmest October day in Tasmania and for warmest October night in Victoria.

A number of stations in northeast New South Wales, southern Queensland, eastern Tasmania, as well as a few in the Northern Territory, observed records for mean maxima or mean minima, averaged across the month as a whole.

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	94	+1.33		106	+1.51	3rd highest (record +2.34 °C in 2015)	99	+1.42	10th highest
Queensland	77	+0.70		106	+2.19	3rd highest (record +2.41 °C in 2005)	102	+1.45	7th highest
New South Wales	= 94	+2.13		107	+2.19	2nd highest (record +3.54 °C in 2015)	105	+2.16	4th highest (record +4.52 °C in 2015)
Victoria	= 96	+2.02		= 95	+0.77		100	+1.40	9th highest
Tasmania	105	+1.80	4th highest (record +3.20 °C in 1914)	105	+1.17	4th highest (record +1.91 °C in 2005)	107	+1.48	2nd highest (record +1.91 °C in 1963)
South Australia	89	+1.48		93	+1.09		= 93	+1.29
Western Australia	94	+1.42		= 97	+1.23		= 96	+1.33
Northern Territory	92	+1.23		98	+1.21		= 96	+1.22

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

For Australia as a whole rainfall was about one and a half times the usual average for October, with very much above average rainfall for Queensland making a strong contribution.

Rainfall for October was above to very much above average for most of Queensland, with monthly totals in the highest 10% of historical observations (decile 1) for October along most of the east coast and adjacent hinterland, extending to the southwest and large parts of northern New South Wales. It was the wettest October on record for parts of the Wide Bay, Burnett and North Tropical Coast districts in Queensland, and for the State as a whole it was the third-wettest October on record; records commence in 1900. Sections of the Queensland east coast, including Bundaberg and Rockhampton, received more than 400% of their average October rainfall.

Above average rainfall was also observed in central New South Wales; parts of the Northern Territory in the northeast, Top End, and across the west of the Alice Springs District; large parts of the north and west of South Australia; and across much of Western Australia from the Kimberley to the southern Interior.

Monthly rainfall was below average for much of the South West Land Division, south coast, and western to central Gascoyne in Western Australia, and also for numerous scattered areas across southeast South Australia and Victoria, and for most of Tasmania.

Heavy rainfall in areas of eastern Queensland between the Central Highlands and Wide Bay and Burnett districts during the first few days of October was associated with a surface trough and upper level disturbance. Very heavy rainfall returned to northeastern New South Wales and southeast Queensland from mid-month, associated with another low level trough and upper level low, with heavy falls also observed around Tully on the North Tropical Coast, and Herbert and Lower Burdekin districts. Riverine flooding resulted around Bundaberg, including major flooding in the Kolan River and Baffle Creek. Daily rainfall records were set at numerous locations along Queensland's east coast on the 17th, 18th or 19th, with totals of 100 mm or more not uncommon, peaking at well over 300 mm at Rosedale and Makowata.

Isolated showers around mid-month brought some record high daily rainfall totals for October in the Central Wheat Belt and Interior districts of Western Australia on the 14th or 15th, in what is typically a time of year with little rainfall.

The passage of a series of cold fronts and associated surface troughs brought widespread rainfall and thunderstorms to much of eastern Australia in the last third of the month.

Area-average rainfall
	Rank (of 118)	Average (mm)	Departure from mean	Comment
Australia	102	36.1	+55%
Queensland	116	69.9	+173%	3rd highest (record 86.1 mm in 1949)
New South Wales	95	57.5	+30%
Victoria	40	46.6	−27%
Tasmania	26	91.1	−26%
South Australia	76	19.6	+7%
Western Australia	103	18.0	+41%
Northern Territory	83	20.8	+10%
Murray-Darling Basin	94	54.7	+36%

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 during October 2017
Hottest day	45.0 °C	at West Roebuck (WA) on the 30th
Coldest day	1.7 °C	at Mount Hotham (Vic.) on the 31st
Coldest night	−5.7 °C	at Thredbo AWS (NSW) on the 31st
Warmest night	30.5 °C	at Bidyadanga (WA) on the 20th
Wettest day	389.0 mm	at Makowata (Qld.) on the 18th

Temperatures Rainfall Extremes Important notes the top

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