Australia in July 2011

In Brief

July 2011 was a generally warmer than normal month for most of Australia, with both maximum and minimum temperatures above normal across most of the country. Parts of eastern Australia had below normal overnight minimum temperatures. Rainfall was mostly close to normal, with the west slightly above average, and the east slightly below average.


Temperatures

Nationally averaged maximum temperatures were 0.60 °C above normal (equal 22nd highest of 62 years of record). No states or territories were ranked in the top or bottom ten of the historical record, however temperatures were above normal for all states and territories for the first time since April 2010, just prior to the recent La Niña of 2010−11.

Most of the country experienced close to average temperatures for the month, with most of Australia within 1 °C of the normal. Small parts of the interior of WA, the southern NT, an area surrounding Moomba in SA, and the Riverina district of NSW all experienced temperatures in excess of 1 °C above normal. The western Kimberley in WA experienced temperatures in excess of 2 °C above normal. This region of the western Kimberley, as well as a small area of the Riverina, recorded maximum temperatures in the highest decile.

Overnight minimum temperatures were also above average, with a national anomaly of +0.41 °C, ranking as the 26th warmest of 62 years. Temperatures were warmer than normal over the southwestern half of the continent and cooler than normal over the northeastern half. Minimum temperatures of 1 °C above normal were measured across most of WA, the western half of SA, southwest coastal Victoria, and parts of the Top End and southwest NT. Anomalies exceeded +3 °C in the northern interior region of WA, extending over the WA-NT border. Large areas of WA, western SA and southwest coastal Victoria recorded overnight minima in the highest decile, with an area near the WA-SA southern border receiving its warmest July minima on record. WA as a whole, had its 4th warmest July minima on record, and SA its equal 8th.

Significant areas of cooler than average minimum temperatures were measured across parts of the central NT, the eastern half of Queensland and small areas of northern NSW, with anomalies locally reaching −1 °C in these areas. Small parts of southeast Queensland recorded anomalies cooler than −2 °C.

Temperatures of note for July include a −11.2 °C on the 23rd at Liawenee, which was the lowest temperature recorded in Tasmania since 1983. Canberra Airport had its lowest temperature since August 1994, with −8.0 °C on the 29th, while Arltunga recorded the lowest temperature in the NT since 2002 with −6.1 °C on the 25th.


Areal average temperatures
  Maximum Temperature Minimum Temperature
Rank
(out of 62)
Anomaly*
(°C)
Comment Rank
(out of 62)
Anomaly*
(°C)
Comment
Australia 40.5 +0.60 37 +0.41
Queensland 39 +0.54 16 −0.82
New South Wales 39 +0.62 24.5 −0.09
Victoria 45 +0.54 49 +0.62
Tasmania 38.5 +0.35 32 +0.18
South Australia 43 +0.74 54.5 +1.16
Western Australia 39 +0.63 59 +1.31 4th highest; record is +2.46 (1973)
Northern Territory 37 +0.53 31.5 +0.03

*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 10% below normal (55th driest of 112 years of record). Most states recorded rainfall on the dry side of normal, with the exception of WA and SA, which recorded above average rainfall.

Above average falls were recorded across a large area of southern WA, western SA and a large area of central Australia. Above average falls were also recorded across the eastern coast of NSW, extending into the Gippsland region of Victoria. This rainfall on the eastern coast was mostly the result of a strong complex low in the region during the second half of the month.

Rainfall significantly below normal was generally confined to parts of the Cape York Peninsula and southeast Queensland, eastern NSW (away from the coast), northwest Victoria and northeast Tasmania. Small areas within these regions recorded rainfall in the bottom 10% of historical records.


Areal average rainfall
Rank
(out of 112)
Average
(mm)
Departure
from mean*
Comment
Australia 55 19.9 −10%
Queensland 54 11.3 −41%
New South Wales 28 23.0 −42%
Victoria 63 69.4 −1%
Tasmania 46 140.2 −12%
South Australia 75 20.5 +10%
Western Australia 79 24.7 +23%
Northern Territory 77 5.0 −28%
Murray-Darling Basin 24 23.7 −41%

*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 July 2011
Hottest day 35.5 °C at Noonamah (NT) on the 17th
Coldest day −3.7 °C at Mount Hotham (Vic) on the 7th
Coldest night −16.0 °C at Charlotte Pass (NSW) on the 27th
Warmest night 25.5 °C at Coconut Island (Qld) on the 7th
Wettest day 130.4 mm at Terrey Hills (NSW) on the 22nd


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 2pm EST on Monday 1 August 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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