Australia in April 2013

In Brief

April maximum temperatures were 1.64 °C above average for Australia as a whole (the fifth-highest on record) and minima 0.55 °C above average. Maxima were above average for most of Australia, excluding the eastern seaboard and parts of the tropical north. For Western Australia April maxima were the third-highest on record. Minima were also above average for most of southern Australia and parts of the tropical north. Minima were below average for the Kimberley coast and southern Queensland and northeastern New South Wales. Southern Western Australia recorded large areas of both highest on record maxima and minima.

Averaged over Australia, April rainfall was below average. Rainfall was generally above average for across the north, below average in the centre and southwest and very much below average in the inland southeast.


Temperatures

April was a warm month for Australia; the eighth consecutive month (since September 2012) with both maximum and minimum temperatures above average. Summer was Australia's warmest on record (maximum and mean temperatures) and January–April was the second warmest such period on record for maximum and mean temperatures (behind 2005 for maximum temperature, behind 1998 for mean temperature). Maxima were above average for Australia as a whole, with a national anomaly of +1.64 °C, the fifth-highest on record. Tasmania was the only State to record below-average maxima. All other States and Territories except Queensland and Victoria exceeded +1 °C with Western Australia's +2.41 °C anomaly its third-highest April maximum anomaly on record and South Australia's +2.00 °C anomaly its seventh-highest.

Maxima were above to very much above average for most of Australia with near-average maxima recorded across the southeastern half of Tasmania, much of the eastern seaboard and parts of the Roper-Macarthur district of the Northern Territory and northern Western Australia. Areas of below-average maxima were observed on the Queensland coast near Kowanyama and more broadly around Rockhampton. Maxima were the highest on record for large areas of southern Western Australia (22% of that State).

The national anomaly for April minima was +0.55 °C. Minima were above to very much above average across most of southern Western Australia, South Australia, northern Victoria and parts of the central Northern Territory and Queensland's tropical coast and adjacent hinterlands. A large area of southwestern and south coast Western Australia recorded highest-on-record April minima (19% of that State). Western Australia's minimum temperature anomaly was the largest departure for the States and Northern Territory and also it's fifth-highest on record at +1.50 °C. Minima were below average for the Kimberley coast and a large area of northern New South Wales and adjacent southern Queensland. Elsewhere minima were near average.


Areal average temperatures
  Maximum Temperature Minimum Temperature
Rank
(out of 104)
Anomaly*
(°C)
Comment Rank
(out of 104)
Anomaly*
(°C)
Comment
Australia 100 +1.64 fifth highest 81 +0.55
Queensland 82.5 +0.82 58 −0.01
New South Wales 84.5 +1.18 50 −0.56
Victoria 84 +0.96 87 +0.52
Tasmania 62.5 −0.23 56 −0.34
South Australia 98 +2.00 seventh highest 77 +0.46
Western Australia 102 +2.41 third highest 100 +1.50 fifth highest
Northern Territory 94 +1.50 67 +0.26

*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

For Australia as a whole, rainfall for the month of April was 19.5 mm, 37% below the long-term average. April rainfall was above average across northern Australia and west coast South Australia. Small areas of eastern tropical Queensland and the western Top End and adjacent Kimberley recorded monthly totals in the highest 10% of records. Southwest Western Australia, central Australia and adjacent parts of Western Australia, most of Tasmania, Victoria and New South Wales recorded rainfall totals below to very much below average. April rainfall totals for most of New South Wales west of the Great Dividing Range, extending through central Victoria to the coast, were in the lowest 10% of records; much of this area in New South Wales recorded little or no rainfall for the month. Ongoing rainfall deficiencies across the inland of the eastern mainland States have been worsened by what was a very dry April for most of this region. New South Wales and Victoria recorded the largest departures from their long-term averages, with those States 68 and 59% below average, respectively.


Area-average rainfall
Rank
(out of 114)
Average
(mm)
Departure
from mean*
Comment
Australia 38 19.5 −37%
Queensland 62 34.1 −19%
New South Wales 16 15.0 −68%
Victoria 17 20.9 −59%
Tasmania 31 83.4 −26%
South Australia 50 9.4 −42%
Western Australia 42 12.4 −41%
Northern Territory 65 20.8 −25%
Murray–Darling Basin 13 9.0 −77%

*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 2013
Hottest day    42.6 °C at Roebourne (WA) on 20 April
Coldest day      0.5 °C at Mount Hotham (Vic.) on 19 April
Coldest night    −5.0 °C at Charlotte Pass (Kosciusko Chalet) on 20 April
Warmest night    28.8 °C at Troughton Island (WA) on 1 April
Wettest day  187.4 mm at Edith Farms Road (NT) on 1 April


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 pm EST on Wednesday 1 May 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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