Thursday 1 February 2018 — Monthly Summary for Australia — Product Code IDCKGC1A00

Australia in January 2018

Temperatures Rainfall Extremes Important notes the top

In brief

• An exceptionally warm month for Australia as a whole, third-warmest January on record
• January was amongst the ten warmest on record for Queensland, New South Wales, Victoria, Tasmania and South Australia
• Mean maximum temperature above average for most of eastern Australia, Central Australia, and South Australia; cooler than average for parts of the northwest
• Mean minimum temperature above average for most of eastern Australia and southern Australia; cooler than average for parts of the Kimberley in Western Australia and western Top End in the Northern Territory
• January rainfall above to very much above average for the western half of Australia and parts of Far Northern Queensland
• Rainfall below average for most of Queensland south of the Cape York Peninsula, northeastern New South Wales, western to central Tasmania, and parts of western Victoria

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Temperatures

January was an exceptionally warm month for Australia as a whole; the monthly mean temperature was the third-warmest on record for January, while the mean maximum temperature was equal eighth-warmest and the mean minimum temperature was equal fifth-warmest. For individual States, January's monthly mean temperature was second-warmest on record for Tasmania and equal second-warmest on record for Queensland. All of the States, except Western Australia and the Northern Territory, ranked amongst the ten warmest on record for both monthly mean maximum and mean minimum temperatures.

Maximum temperatures were above average across nearly all of the eastern States (Queensland, New South Wales, Victoria and Tasmania), South Australia, and the southern half of the Northern Territory. Maxima were in the warmest 10% of historical observations (decile 10) for January across most of this area. A number of stations across southern Queensland, New South Wales, Victoria and Tasmania had their warmest mean maximum temperature on record for January. Hobart just missed out; the mean daily maximum temperature for Hobart (Ellerslie Road) was 24.4 °C, 2.7 °C above the long-term average and second-warmest on record for January.

Maxima were below average for much of the Kimberley and eastern Pilbara in Western Australia, extending into part of the Interior District, and across the south of the Top End to parts of the Gulf coast. This corresponds to areas which received very much above average rainfall for the month.

Minimum temperatures for the month were above average across the eastern States, South Australia, the southwest of the Northern Territory, and most of the southern half of Western Australia, extending northward through the Gascoyne and western half of the Pilbara. However, minima were near average for the southwest of Western Australia and along much of the east coast of Queensland. Minima were also near average for most of the remainder of the Northern Territory and the remainder of the northern half of Western Australia. Minima were below average for regions adjacent to the coast of the western Top End and of the Kimberley.

A pulse of warm weather travelled along the southern coast during the first week of the month, culminating in a short-lived heatwave over the southeast between the 6th and 7th. Some sites, mostly in the Sydney region, recorded their highest January temperature on record on the 7th, including 47.3 °C at Penrith Lakes AWS, which is Greater Sydney's second-warmest day on record (Richmond holds the record of 47.8 °C in January 1939). Several hundred flying foxes died in Sydney's western suburbs, while in Victoria the hot conditions were associated with more than 100 grass- and bushfires, although fortunately causing relatively little property damage.

The month came to a very warm end in the southeast when hot and very humid air fed down from Queensland into Victoria and Tasmania. Several sites in central and southern Tasmania reached temperatures in the high 30s on the 28th, while temperatures peaked in the mid-40s in Victoria. Overnight temperatures were particularly notable, with many sites setting January records in Tasmania on the 28th or 29th, and a handful in Victoria and New South Wales. Following the heatwave, a strong cool change brought below average temperatures for the last two days of the month, some locally heavy rainfall, and snow in the highlands of Tasmania.

Areal average temperatures
	Maximum Temperature			Minimum Temperature			Mean Temperature
	Rank (of 109)	Anomaly (°C)	Comment	Rank (of 109)	Anomaly (°C)	Comment	Rank (of 109)	Anomaly (°C)	Comment
Australia	= 101	+1.32	equal 8th highest	= 104	+1.23	equal 5th highest	107	+1.28	3rd highest (record +1.77 °C in 2013)
Queensland	105	+2.26	5th highest	107	+1.72	3rd highest (record +2.25 °C in 2006)	= 107	+1.99	equal 2nd highest (record +2.00 °C in 2013)
New South Wales	107	+3.78	3rd highest (record +4.56 °C in 1939)	104	+2.46	6th highest	105	+3.12	5th highest
Victoria	106	+3.17	4th highest (record +3.63 °C in 1981)	104	+2.32	6th highest; highest since 2006	106	+2.75	4th highest (record +3.27 °C in 2001)
Tasmania	108	+2.59	2nd highest (record +2.91 °C in 1961)	101	+1.09	9th highest	108	+1.84	2nd highest (record +2.12 °C in 1961)
South Australia	100	+2.42	10th highest	100	+2.13	10th highest	102	+2.28	8th highest
Western Australia	50	−0.04		89	+0.43		67	+0.20
Northern Territory	61	−0.07		84	+0.44		73	+0.19

Rank ranges from 1 (lowest) to 109 (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

Rainfall for Australia as a whole was above average for January. January rainfall was above average across Western Australia, most of South Australia west of Spencer Gulf, most of the Northern Territory, and much of the Cape York Peninsula in Queensland. Monthly rainfall was below average for most of Queensland south of the Peninsula and across the northeastern third of New South Wales, reaching as far south along the coast as the Illawarra District. Rainfall for January was also below average for most of Tasmania away from the east, and across southwestern and northwestern Victoria and adjacent parts of southeast South Australia.

Tropical cyclone Joyce during the first half of the month, and a slow-moving tropical low later in the month, produced widespread significant rainfall over the Northern Territory and Western Australia. For Western Australia as a whole, it was the fifth-wettest January on record. Numerous stations in Western Australia and the Northern Territory observed their highest monthly rainfall total on record for January.

As an ex-tropical cyclone, the remnant low associated with Joyce brought heavy rainfall along the west coast of Australia, including in the Perth region, between the 14th and 16th, with many sites observing record high daily rainfall totals for January.

The monsoon trough became active over northern Australia from about the 18th, with monsoon onset in the Northern Territory officially occurring on 21 January (equal fourth-latest onset since 1957). Monsoon activity continued to the end of the month, with frequent heavy rain over the Cape York Peninsula, and a tropical low forming over the Top End around the 20th. The low was slow-moving as it gradually progressed in a southwesterly direction, finishing the month over the Pilbara. A couple of sites in the Northern Territory had their highest January daily rainfall on record during the 24 hours to 9 am on the 28th. Major flooding occurred on the Daly River leading to the evacuation of the township.

The end of the month also brought a wet few days for the southeast associated with the passage of a strong cold front, with locally heavy falls and some thunderstorms affecting Victoria and Tasmania. On the 28th Wangaratta Aero had its highest January daily rainfall on record. Most of the rain fell in an hour, with the intensity for durations of 30 minutes to 3 hours having an annual exceedance probability of less than 1% (a less frequent than a 1-in-100 year event at those durations).

Area-average rainfall
	Rank (of 119)	Average (mm)	Departure from mean	Comment
Australia	100	99.9	+25%
Queensland	31	82.6	−35%
New South Wales	28	30.1	−54%
Victoria	56	33.4	−16%
Tasmania	24	49.4	−35%
South Australia	81	20.7	−15%
Western Australia	115	119.0	+110%	5th highest
Northern Territory	106	203.7	+70%
Murray-Darling Basin	22	22.2	−60%

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 January 2018
Hottest day	47.4 °C	at Marree Aero (SA) on the 22nd and Wudinna Aero (SA) on the 19th
Coldest day	6.5 °C	at Mount Baw Baw (Vic.) on the 30th
Coldest night	−1.5 °C	at Mount Hotham (Vic.) on the 14th
Warmest night	34.4 °C	at Birdsville Airport (Qld.) on the 12th
Wettest day	448.8 mm	at West Roebuck (WA) on the 30th

Temperatures Rainfall Extremes Important notes the top

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