Tuesday 1 September 2015 — Monthly Summary for Australia — Product Code IDCKGC1A00
Australia in August 2015
August rainfall was below average for most of Victoria except Gippsland, southeast South Australia, northern Tasmania, along the west coast of Western Australia and between the Pilbara and adjacent inland regions, as well as for pockets of Queensland. Rainfall was higher than average for much of southern Western Australia away from the west coast, the central Northern Territory, southeastern New South Wales and eastern Victoria, and an area stretching from western New South Wales across northern agricultural districts of South Australia. Nationally, rainfall was 11% below average.
Maximum temperatures were warmer than average in a broad band running around the coast of Australia from southwest Western Australia, across the north, to about halfway down the New South Wales coast. Above-average maxima also extended across southern Queensland into northeastern South Australia and across much of the northern interior of Western Australia. Maximum temperatures were below average for a large part of the mainland southeast, and very much below average for most of Tasmania. Nationally, maximum temperatures were 0.68 °C warmer than average.Minimum temperatures were above to very much above average across most of Western Australia, extending into the western half of South Australia, and also for areas of eastern Australia. Minima were very much below average for Tasmania and below average for some parts of northern Australia. Nationally, minimum temperatures were 0.53 °C above average.
The national August mean temperature was 0.61 °C above the long-term mean. Both maximum (+0.68 °C) and minimum (+0.53 °C) temperatures were above average for the country as a whole.
Tasmania, however, broke the trend with both maxima and minim well below average—maximum temperatures were the equal-eighth coolest on record for August and minimum temperatures the fourth coolest for August. Overall, Tasmanian mean temperatures were the equal-third coolest on record for August. Tasmania experienced snow to low levels twice early in the month and again around mid-month. Several sites set records for low daily or monthly temperatures, both for maxima and minima as well as for mean temperatures.
The first third of the month was generally cooler than average for much of Australia, particularly in the east and the north. From around mid-month the passage of a slow-moving high pressure system across Australia brought above-average temperatures to the west of Australia, including some daily maximum temperature records in the Southwest district on the 15th and 16th and warm minima for the 24 hours to 9 am on the 17th, with above-average temperatures reaching the eastern States on the 21st. A number of locations in inland Queensland observed their warmest August overnight temperatures during the 24 hours to 9 am on the 24th. Above-average temperatures contracted into the north during subsequent days, while the last week of the month again saw warmer-than-average days for Western Australia.
Maximum temperatures were warmer than average across much of Western Australia, except for an area of the southern interior to south coast, as well as across the top of the Northern Territory and through most of Queensland, except parts of the inland west and the Darling Downs. Maximum temperatures were also above average along the coast of northern to central New South Wales and in an area of northeastern South Australia. Daytime temperatures were in the highest 10% of historical observations (decile 10) for small areas in the northwest of Western Australia, around the Gulf coast, and along the east coast. Maxima were cooler than average for most of Victoria except the northwest, parts of southeastern South Australia and the Flinders and Eyre Peninsula districts, the Riverina district of New South Wales, and all of Tasmania. For the southern half of Tasmania minima were in the lowest 10% of historical observations (decile 1).
Minimum temperatures were warmer than average for most of Western Australia, except the Kimberley, and the western half of South Australia. Minima were in the highest 10% of historical observations (decile 10) for the majority of the southern half of Western Australia and adjacent parts of South Australia as well as for smaller parts of the western Pilbara and norther Interior district. Minima were also above average for southwestern New South Wales, southwestern and coastal southeastern Queensland, a region south of the Gulf of Carpentaria and other scattered small areas of the eastern States. Minimum temperatures were below average for an area between the eastern Kimberley and Alice Springs, other small pockets in the eastern Top End, the Cape York Peninsula, near Rockhampton, and northwestern New South Wales. Minima were in the lowest 10% of historical observations (decile 1) for Tasmania.
|Areal average temperatures|
|Maximum Temperature||Minimum Temperature||Mean Temperature|
|New South Wales||62||+0.24||= 77||+0.43||= 67||+0.34|
|Tasmania||= 8||−0.96||equal 8th lowest; lowest since 1978||4||−1.60||4th lowest (record −1.96 °C in 1943)||= 3||−1.27||equal 3rd lowest (record −1.40 °C in 1943)|
|South Australia||= 66||+0.54||= 79||+0.79||75||+0.67|
|Western Australia||84||+1.12||= 97||+1.07||equal 9th highest||= 93||+1.10|
Rank ranges from 1 (lowest) to 106 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Anomaly is the departure from the long-term (1961–1990) average.
Nationally-averaged rainfall during August was 11% below the long-term mean. The Northern Territory observed area-averaged rainfall above the long-term mean owing to moderate falls in the northern Alice Springs district during the last week of the month. August is part of the dry season for northern Australia so these falls were not typical for the time of year.
In addition to above-average rainfall in the central to southern Northern Territory, rainfall was also above average for the south of Western Australia away from the west coast, extending just into southwestern South Australia, along a band extending from near Ceduna through northern agricultural districts of South Australia into western New South Wales, in an area of the highlands of the southeastern quadrant of Queensland, and in an area of southeastern New South Wales and across Gippsland in Victoria.
Above-average rainfall in southeastern New South Wales and eastern Victoria was largely a result of very heavy falls associated with an East Coast Low late in the month. A low pressure system crossed New South Wales during the 23rd and 24th, triggering thunderstorms including a tornado observed at Dubbo, before deepening once offshore overnight on the 24th. The system produced 48-hour totals in excess of 300 mm to 9 am on the 26th for parts of the Illawarra and South Coast districts of New South Wales, including some daily records for August rainfall. Heavy rain continued in Victoria on the backside of the low, with some parts of the State receiving record-high August daily rainfall for the 24 hours to 9 am on the 28th.
Numerous sites in the southwest of Western Australia and the Southeast Coast district, including a few with over 100 years of records, observed their highest August daily rainfall on record for the 24 hours to 9 am on the 1st, associated with a complex system of low pressure and surface troughs.
August rainfall was below average for southeast South Australia and most of Victoria except Gippsland, for northern Tasmania, a narrow strip along the west coast of Western Australia and a broad area of the western Pilbara. Rainfall was also below average in parts of the northern Interior district to eastern Kimberley, as well as for smaller areas in Queensland in the inland south and pockets of the north. Areas of below-average rainfall in parts of northern Australia generally reflect very small negative anomalies as August is typically a dry month for northern Australia away from the greater southeast and eastern coastal margin of Queensland the northern dry season spans May to September).
|New South Wales||61||36.3||−4%|
Rank ranges from 1 (lowest) to 116 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Departure from mean is relative to the long-term (1961–1990) average.
|Australian weather extremes during August 2015|
|Hottest day||37.6 °C at Warmun on 25 August (WA)|
|Coldest day||−4.7 °C at Mount Hotham (Vic.) on 4 August|
|Coldest night||−12.8 °C at Perisher Valley AWS (NSW) on 4 August|
|Warmest night||25.4 °C at McCluer Island (NT) on 25 August|
|Wettest day||277.6 mm at Kangaroo Valley (Main Rd) (NSW) on 26 August|
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. Later information, including data that has had greater opportunity for quality control, will be presented in the Monthly Weather Review, usually published in the fourth week of the month.
Climate Summaries are usually published on the first working day of each month.
This statement has been prepared based on information available at 10 am EST on Tuesday 1 September 2015. 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.
The system used for calculating areal averages of rainfall was changed in August 2009; the main effect was that current and historical values for Tasmania were increased. Since August 2012, ACORN-SAT has been used for calculating areal averages of temperature; the major change from earlier datasets is that the ACORN-SAT dataset commences in 1910, and hence rankings are calculated using a larger set of years.