Australia in December 2012

In Brief

December rainfall was below average across most of the eastern States as well as the Top End and southern South Australia. Above-average rainfall was recorded in the central Northern Territory and most of Western Australia. For Australia as a whole, the monthly rainfall total was somewhat below average. Maximum temperatures were above to very much above average for most of Australia during December, with isolated parts of the far northern coasts observing record high maxima. Below-average daytime temperatures were recorded around the Pilbara and Gascoyne in WA, as well as isolated areas in the northern inland of Western Australia and the Northern Territory. Minimum temperatures were generally above average for Australia, although parts of the southeast recorded near-average monthly minima and parts of the north observed cooler-than-average nights.


Temperatures

The December-averaged maximum temperature was the fourth-highest on record for Australia as a whole. The national anomaly was +1.23 °C; no State or Territory recorded a negative monthly anomaly for maxima. Queensland's monthly anomaly was its fifth highest (+1.70 °C), and South Australia's its fourth highest and the largest anomaly for any State (+2.17 °C).

Maximum temperatures were above to very much above average across central and southern Australia during December, as well as around the extreme northern coasts. An arc extending from the Pilbara coast through the northern inland to central Queensland generally observed near-average maxima, with below-average daytime temperatures recorded around the Pilbara and Gascoyne in Western Australia, as well as isolated areas in the northern inland of Western Australia and the Northern Territory. Much of the north of the Cape York Peninsula observed record-high December maxima, as did the coast of the western Top End, and a small area around Broome. Monthly temperatures were 2 to 4 °C above average across much of inland Queensland and adjacent parts of New South Wales and South Australia.

Minima were also consistently above average for all States and the Northern Territory. The national-average monthly minimum temperature was 0.92 °C above average. Western Australia recorded its third-highest December minimum temperature anomaly.

Minimum temperatures were above average for most of mainland Australia, with much of Western Australia and central Australia in the highest 10 per cent of records. Minima were near average for most of Tasmania, southern South Australia, northwestern Victoria, and eastern Victoria extending into the tablelands of New South Wales. Small areas near Uluru and on the Pilbara coast recorded highest-on-record December minima. Eastern Queensland generally recorded near-average minima, with small areas inland of Cooktown and Rockhampton recording below-average minima. Nights were also cooler than average in the central Northern Territory and Kimberley. Minimum monthly anomalies of +2 to 4 °C were recorded in much of central Australia.


Areal average temperatures
  Maximum Temperature Minimum Temperature
Rank
(out of 103)
Anomaly*
(°C)
Comment Rank
(out of 103)
Anomaly*
(°C)
Comment
Australia 100 +1.23 fourth highest, highest since 1979 98 +0.92
Queensland 99 +1.70 fifth highest 90 +0.82
New South Wales 92 +1.89 92 +1.47
Victoria 86 +1.49 83 +0.77
Tasmania 77.5 +0.90 63 +0.19
South Australia 100 +2.17 fourth highest 95.5 +1.34
Western Australia 89 +0.65 101 +0.84 third highest, highest since 1977
Northern Territory 82.5 +0.54 87.5 +0.62

*Anomaly is the departure from the long-term (1961–1990) average.
A fractional rank indicates that the value is tied for that rank.


Temperature maps
MeanAnomalyDeciles
Mean
daily
maximum
temperatures
Map of mean daily maximum temperature Map of mean daily maximum temperature anomalies Map of mean daily maximum temperature deciles
Mean
daily
minimum
temperatures
Map of mean daily minimum temperature Map of mean daily minimum temperature anomalies Map of mean daily minimum temperature deciles

Rainfall

December rainfall was below average across the Queensland coast and ranges, and most of inland New South Wales; small parts of this area recorded their lowest December total on record. Rainfall was also below average across discontinuous parts of the Top End, southern South Australia, large parts of Victoria, and western Tasmania. The western half of Western Australia, the Kimberley, and central Northern Territory recorded above-average rainfall. Much of the Pilbara, Gascoyne, and coast further south recorded rainfall in the highest 10 per cent of records, with totals more than 50 mm above the December average widespread. For Australia as a whole, the monthly rainfall total was somewhat below average, at 45.3 mm compared to the long-term average of 52.3 mm. Western Australia recorded December rainfall 58 per cent above average, the Northern Territory near-average, and the other mainland States between 37 and 48 per cent below average.


Area-average rainfall
Rank
(out of 113)
Average
(mm)
Departure
from mean*
Comment
Australia 41 45.3 −13%
Queensland 22 43.4 −47%
New South Wales 34 32.0 −41%
Victoria 33 30.1 −37%
Tasmania 47 85.1 −18%
South Australia 34 9.6 −48% lowest since 1994
Western Australia 88 50.1 +58%
Northern Territory 59 74.6 0%
Murray-Darling Basin 37 30.3 −38%

*The mean is calculated for the 1961–1990 reference period.


Rainfall maps
TotalsPercentagesDeciles
Total
rainfall
Map of total rainfall Map of percentage of normal rain Map of rainfall deciles


Australian weather extremes in December 2012
Hottest day    47.3 °C at Emu Creek (WA) on 23 December
Coldest day    −0.2 °C at Mount Baw Baw (Vic) on 4 December
Coldest night    −5.3 °C at Perisher Valley (NSW) on 10 December
Warmest night    32.7 °C at Emu Creek (WA) on 24 December
Wettest day  210.8 mm at Yourdamung Lake (WA) on 13 December


Notes

The Monthly Climate Summary is prepared to list the main features of the weather in Australia using the most timely and accurate information available on the date of publication; it will generally not be updated.

This statement has been prepared based on information available at 12 noon EST on Wednesday 2 January 2013. Some checks have been made on the data, but it is possible that results will change as new information becomes available, especially for rainfall where much more data becomes available as returns are received from volunteers.

Long-term averages in this statement and associated tables are for the period 1961 to 1990 unless otherwise specified.

In the tables, fractional ranks denote tied values.

A new area-averaging method was adopted for rainfall in May 2009. Current and historical totals for Tasmania are substantially higher than under the old scheme, but differences for other states, and nationally, are negligible. The rankings and departures from mean shown here use the new method.

The new ACORN-SAT temperature dataset has been used for calculation of State and national temperature area averages in summaries from December 2012 onwards. The major change from earlier datasets is that the ACORN-SAT dataset commences in 1910, rather than 1950, and hence rankings are calculated using a larger set of years.


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