Australia in September 2010

In Brief

September 2010 had mostly cooler than normal daytime temperatures. Australia as a whole had its coolest maximum temperatures since 1984. Most states had their coolest daytime temperatures in at least 17 years. Australia had its wettest month on record, with an area average of 48.8mm, +194% above normal.


Temperatures

Nationally averaged maximum temperatures were cooler than normal for September. Daytime maximum temperatures were 1.20C lower than normal, making it the coldest September since 1984 (26 years). The NT also had its coolest maximum temperatures since 1984. Queensland and NSW had their coolest maximums since 1993, with Victoria and WA, since 1992. SA had its second lowest maximum temperatures on record.

Maximum temperature anomalies of −1C to −2C were located in southern Tasmania and a large region stretching from southern Queensland down to Victoria. Stronger anomalies were located further west, covering a large region from southwest Queensland and western NSW across to the eastern half of WA, in which maximum temperatures were 2C to 6C below normal. The coolest of these anomalies were concentrated near the WA and SA border, stretching into central WA and the southern NT; these were areas of lowest on record. SA as a whole, had its second lowest maximum temperatures on record for September.

Above average maximum temperatures were mostly confined to the more coastal areas. The west coast of WA, stretching from Carnarvon to Busselton, had temperatures 1C to 2C above normal, while the tropics had temperatures of 1C to 3C above normal. A small region surrounding Darwin and a larger area in the Gulf Country region of Queensland had highest on record maximum temperatures.

Overnight minimum temperatures for Australia as a whole, were 0.90C above normal. Generally, the northern areas of Australia were warmer than normal, while the southern areas were cooler than normal.

Notable cooler than normal minimum temperatures were located in the Riverina district of NSW as well as southern and central WA, where minimum temperatures were 1C to 2C below normal. Small areas of WA near Katanning, Norseman and Meekatharra had anomalies of −2C to −3C. The area near Katanning had its lowest on record minimum temperatures for September.

Notable warmer than normal minimum temperatures were located in northern WA, the northern NT, Queensland and northeast NSW, where minimum temperatures were at least 1C above normal. These areas were all in the 10th decile for September. The warmest anomalies were concentrated in the northern NT and a region of Queensland, just south of the Peninsula region, where minimum temperatures were more than 4C above normal. Large areas had their warmest minimum temperatures on record for September. The Darwin-Daly and Roper-McArthur regions of the NT, most of the northern half of Queensland, a small area near Derby in WA, and a small area near the coastal border of NSW and Queensland all had their warmest September minimums on record. Queensland as a whole, had their second warmest overnight temperatures for September.


Areal average temperatures
  Maximum Temperature Minimum Temperature
Rank
(out of 61)
Anomaly*
(°C)
Comment Rank
(out of 61)
Anomaly*
(°C)
Comment
Australia 8 −1.20 Lowest since 1984 46 +0.90
Queensland 22 −0.23 Lowest since 1993 60 +2.92 2nd highest; record is +3.41 (1998)
New South Wales 15 −0.61 Lowest since 1993 41 +0.60
Victoria 8 −1.29 Lowest since 1992 25 −0.22
Tasmania 7 −0.94 40 +0.19
South Australia 2 −2.64 2nd lowest; record is −3.09 (1958) 34 +0.46
Western Australia 7 −1.44 Lowest since 1992 23 +0.04
Northern Territory 9 −1.32 Lowest since 1984 34 +0.62

*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

Nationally averaged rainfall was wettest on record for the month, with area averaged rainfall 194% above normal. Queensland and the NT had their wettest September on record and further to this, SA and WA had their third wettest September. The Murray Darling Basin region also had a reasonably wet month, with rainfall 78% above normal; its wettest since 1998. A special climate statement discusses this wet month, and compares it to the long-term rainfall deficits.

Only small areas of Australia received below average rainfall. These were southwest WA, south of a line from Carnarvon to Esperance, the Gippsland region of Victoria, a small region surrounding Newcastle in NSW and a few small scattered areas in the Roper-McArthur district in the NT.

Most of the country had a very wet month. Areas of rainfall in the top decile covered most of Queensland, stretching slightly across the border into NSW, most of WA, except the southwest, and large areas of the NT and SA. Smaller areas of decile ten falls were located in central Victoria and western Tasmania.

Significant areas of Australia had their highest rainfall on record for September. Large areas scattered across the continent, stretching from Port Headland in WA across to Rockhampton in Queensland, had highest on record falls. Other areas of highest on record included the border region of WA and SA, small areas in the Top End of the NT and the Peninsula region of Queensland.


Areal average rainfall
Rank
(out of 111)
Average
(mm)
Departure
from mean*
Comment
Australia 111 48.8 +194% Highest on record
Queensland 111 76.0 +490% Highest on record
New South Wales 93 50.9 +44%
Victoria 63 67.3 +3%
Tasmania 85 171.1 +24%
South Australia 109 48.6 +184% 3rd highest; record is 51.4 (1979)
Western Australia 109 29.3 +178% 3rd highest; record is 35.6 (1904)
Northern Territory 111 40.5 +479% Highest on record
Murray-Darling Basin 102 60.6 +78% Highest since 1998

*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 September 2010
Hottest day 42.7 °C at West Roebuck (WA) on the 28th
Coldest day −2.6 °C at Mount Hotham (Vic) on the 16th
Coldest night −12.1 °C at Charlotte Pass (NSW) on the 8th
Warmest night 29.4 °C at Wyndham (WA) on the 25th
Wettest day 185.9 mm at Falls Creek (Vic) on the 5th


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 Friday 1 October 2010. 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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