Australia in April 2011

In Brief

Rainfall was slightly above average across Australia, with large areas (particularly in the south) recording mostly near-average rainfall. Temperatures were cooler than normal for both day time and night time temperatures.


Temperatures

Maximum temperatures were 0.67°C below normal (14th lowest on record) with most states and territories recording below average day time temperatures. The most significant cool conditions were recorded across northern Australia with the NT recording its 4th coolest April on record for maximum temperatures with temperatures in northwest NT and east Kimberley up to 4 degrees below normal. The area in the north and east Kimberley extending to the western border of the NT recorded its coolest April on record. Queensland also experienced cool conditions with large areas recording day time temperatures up to 3 degrees below normal.

Tasmania was the only state to record warmer conditions during April however the strongest warm anomalies were recorded over southern and western WA which recorded day time temperatures in excess of 3 degrees above the April average. An area around Shark Bay on the west coast of WA recorded its warmest April on record. The strong warm and cool anomalies in WA were comparative in strength and spatial extent as the resulting average across the state was 0.05 degrees below normal.

Minimum temperatures were 0.96°C below normal (10th lowest on record) across Australia with the NT recording its lowest April on record for minimum temperatures. The pattern of minimum temperature anomalies was similar to the maximum temperatures with most states recording below average night time temperatures. The coolest minimum temperature anomalies in excess of 3 degrees below normal were recorded in the interior of Queensland and the NT. Western WA recorded the strongest warm night time temperatures of up to 2 degrees above normal.


Areal average temperatures
  Maximum Temperature Minimum Temperature
Rank
(out of 62)
Anomaly*
(°C)
Comment Rank
(out of 62)
Anomaly*
(°C)
Comment
Australia 14 −0.67 10 −0.96
Queensland 11 −0.98 Lowest since 2000 8 −1.25
New South Wales 22 −0.28 52 +1.49
Victoria 22 −0.41 23 −0.84
Tasmania 47 +0.55 37 +0.11
South Australia 23 −0.27 16 −0.77
Western Australia 23 −0.05 26 −0.08
Northern Territory 4 −2.09 Lowest since 2000 1 −2.40 Lowest on record; previous record − 1.93 (1950)

*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 18% above normal (32nd highest out of 112 years of record). Northern Australia recorded above average falls in particular over the northern half of the NT and the Kimberley. Parts of eastern Queensland as well as the NSW and Tasmanian east coast also received above average falls partly associated with the dominant easterly flow along the coast during the month. Central Australia experienced drier conditions with a large area of below average rainfall recorded across parts of southern NT, northern SA and parts of eastern WA and southwest Queensland. Most of this area received little or no rain during the month. April 2011 is the first month with below-normal rainfall since June 2010 for Queensland, SA and NSW, and since July 2010 for Victoria.

The wet conditions over the tropical north were associated with an active monsoon trough at the start of April and also Tropical Cyclone Errol which developed off the northwest coast of the NT and contributed to a small area in the northeast Kimberley recording its wettest April on record. Rainfall over eastern and southern parts of Australia was partly associated with the passage of several surface low pressure troughs as well as a strong cold front during the middle of the month.

Most areas in the southern half of the country recorded near-average falls; with the exception of some scattered patchy areas which recorded slightly above or below average conditions (see rainfall deciles map below).


Areal average rainfall
Rank
(out of 112)
Average
(mm)
Departure
from mean*
Comment
Australia 80 36.2 +18%
Queensland 70 36.7 −12.3%
New South Wales 55 31.9 −32%
Victoria 51 40.9 −20%
Tasmania 49 104.1 −7%
South Australia 31 4.8 −70%
Western Australia 88 34.3 +64%
Northern Territory 97 61.4 +120%
Murray-Darling Basin 54 24.4 −14%

*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 April 2011
Hottest day 40.0 °C at Roebourne (WA) on the 14th
Coldest day 0.8 °C at Thredbo (NSW) on the 13th
Coldest night −5.1 °C at Perisher Valley (NSW) on the 23rd
Warmest night 29.5 °C at Pardoo (WA) on the 28th
Wettest day 206.0 mm at Mt Hart (WA) 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 Monday 2 May 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.


Further information

Media
(03) 9669 4057
Enquiries