Australia in December 2010

In Brief

December was another exceptionally wet month through most of Australia. It was the second-wettest December on record for the country as a whole, and the wettest December on record for Queensland. This resulted in widespread flooding in eastern Australia. It was also a rather cool month for most of the country, particularly for daytime maximum temperatures.


Temperatures

Daytime maximum temperatures were below normal through most of the country, with the national average anomaly of −1.35C the equal second lowest on record, and Queensland, New South Wales and the Northern Territory all ranking in the bottom five. Only a few parts of the country had above-normal maximum temperatures, notably the interior of Western Australia and the states west coast south of Carnarvon; other areas with maxima slightly above normal were the southern coastal fringe of South Australia and Victoria, and north Queensland north of Townsville.

Elsewhere, daytime temperatures were below normal. They were at least 2C below normal in most of inland Queensland and northern New South Wales, along with the eastern Northern Territory, and were in the lowest decile over most of this region. Over southern and central inland Queensland, and adjacent areas of northern New South Wales, they were 3 to 5C below normal, with records set locally in the Central Highlands and Darling Downs of Queensland, and northern New South Wales.

Minimum temperatures were closer to normal with the national mean 0.19C below average, with nights cooler than normal in the central and eastern interior and warmer than normal in most other areas. Areas with above-normal minimum temperatures included most of Western Australia except for the Kimberley, Victoria, the eastern halves of Queensland and New South Wales, Tasmania (except the far south), and the agricultural areas of South Australia.

Minima were 1-2C below normal over a region of the eastern interior encompassing far western Queensland, the southeast Northern Territory, northeast South Australia and far northwest New South Wales, although they only reached the lowest decile in a few places. In contrast, they were 1-3C above normal in western Western Australia between Perth and Port Hedland, with records set locally around North-West Cape.


Areal average temperatures
  Maximum Temperature Minimum Temperature
Rank
(out of 61)
Anomaly*
(°C)
Comment Rank
(out of 61)
Anomaly*
(°C)
Comment
Australia 2.5 −1.35 Equal 2nd lowest on record; record is −1.92 (1999) 26 −0.12
Queensland 4 −2.41 Lowest since 2000 31.5 −0.01
New South Wales 5 −2.18 Lowest since 1999 26 −0.21
Victoria 23 −0.63 40.5 +0.37
Tasmania 27 −0.11 31 +0.01
South Australia 18 −0.94 26.5 −0.05
Western Australia 27 −0.43 45 +0.32
Northern Territory 5 −1.66 Lowest since 2000 5.5 −1.22 Lowest since 1978

*Anomaly is the departure from the long-term (1961-1990) average.


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

Rainfall averaged over Australia was 99% above normal, and ranked only behind December 1975. A record was set in Queensland (+154%), with Victoria ranking fifth and New South Wales eighth. Rainfall was above normal almost throughout the eastern states, the only significant exceptions being southern Tasmania, parts of coastal New South Wales around Sydney and Newcastle, and some areas west of Melbourne. Further west, it was also drier than normal in most of southern Western Australia from Perth southwards, as well as in the states interior and adjacent parts of far western South Australia and the southwest Northern Territory.

Large areas of the country had rainfall in the highest decile. These included most of the eastern half of Queensland, the ranges and western slopes of New South Wales (except in the far north), northern and western Victoria, and South Australia south and east of Port Augusta. Another area with rainfall in the highest decile was the Gascoyne region of Western Australia. December records were set in numerous areas, most notably in much of the southeast quarter of Queensland, a band extending from Canberra to Dubbo, areas on either side of the Victoria-South Australia border, and areas around and inland from Carnarvon. No significant areas had rainfall in the lowest decile.


Areal average rainfall
Rank
(out of 111)
Average
(mm)
Departure
from mean*
Comment
Australia 110 104.0 +99% 2nd highest; record is 107.9 (1975)
Queensland 111 209.5 +154% Highest on record; previous record 200.1 (1975)
New South Wales 104 98.9 +83%
Victoria 107 103.9 +118% Highest since 1992
Tasmania 83 122.9 +18%
South Australia 84 27.4 +49%
Western Australia 91 53.7 +68%
Northern Territory 91 121.0 +63%
Murray-Darling Basin 110 107.0 +119% 2nd highest; record is 120.7 (1992)

*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 2010
Hottest day 47.6 °C at Gacoyne Junction (WA) on the 27th
Coldest day 1.2 °C at Mount Hotham (Vic) on the 19th
Coldest night −4.4 °C at Mount Hotham (Vic) on the 28th
Warmest night 32.1 °C at Warburton (WA) on the 31st
Wettest day 304.0 mm at Corsis (Qld) on the 25th


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 on Wednesday 5 January 2011. 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.


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