Australia in spring 2017

In Brief

  • Spring national mean temperature very much above average; nationally sixth-warmest on record for spring
  • Both maxima and minima exceptionally warm for Australia as a whole
  • Mean minimum temperature amongst the ten warmest on record for all States, but not the Northern Territory
  • Mean maximum temperature amongst the ten warmest on record for Victoria, Tasmania, and Western Australia
  • Rainfall above average nationally; but mixed over individual months and across Australia geographically
  • September particularly dry for the southeastern mainland and Queensland; record dry for the Murray-Darling Basin
  • Third-wettest October on record for Queensland, above average rainfall in northern New South Wales
  • November rainfall closer to average, but very dry for Tasmania and Gippsland while wet for the Northern Territory and South Australia

Temperatures

Spring 2017 was exceptionally warm for Australia. All regions except South Australia and the Northern Territory observed mean temperatures for the season amongst the ten warmest on record, and for Australia as a whole it was the sixth-warmest spring. Both maximum and minimum temperatures were above to very much above average over the majority of Australia. Since 1994, a cooler than average spring mean temperature for Australia has been observed in only two years.

The mean maximum temperature was the tenth-highest on record for Australia as a whole. Daytime temperatures for spring were above average for nearly all of Australia, and in the highest 10% of historical observations (decile 10) for much of the southeast and around the northern coastline between the Gulf of Carpentaria and the northern Interior District in Western Australia. Near-average maxima were observed along most of the east coast of Queensland south of the Cape York Peninsula, and in the Victoria River District in the Northern Territory.

Mean minimum temperatures were above to very much above average for most of Australia and the equal-ninth warmest on record for Australia as a whole. Minima were in the highest 10% of historical observations (decile 10) for large areas including along the northwest coast and across the South West Land Division in Western Australia, from the Nullarbor to Victoria and through much of western New South Wales and western Queensland, and also in coastal southeastern Queensland and across Tasmania. Minima were generally near average for the Northern Territory south of the Top End and adjacent parts of Western Australia. Below average minima for spring were observed in areas of the eastern Kimberley and northern Alice Springs districts.

Each of the individual months of spring was warmer than average nationally, with warmth most notable for maximum temperatures across the majority of the mainland during September, for both maxima and minima across most of Australia during October, and for both maxima and minima across southern Australia during November. Large areas of eastern Queensland and parts of northeastern New South Wales observed cooler than average maxima and minima during November.

Several periods of exceptional warmth contributed to the very warm spring. High temperature records for September were set in Victoria, New South Wales, and Queensland during the last week of that month associated with a favourable synoptic situation of Tasman Sea high pressure systems and troughs over central Australia (see Special Climate Statement Exceptional September heat in eastern Australia). A strong blocking high in the Tasman was also responsible for an extended period of very warm weather during November across southeastern Australia, during which significant records for runs of consecutive warm days were set. A Special Climate Statement will be released shortly summarising that event.

Abnormally high temperatures throughout spring occurred in the absence of Australia's most important large-scale climate drivers; El Niño–Southern Oscillation and the Indian Ocean Dipole were both neutral. Towards the end of the season the Pacific Ocean showed signs of moving towards a more La Niña-like state. The long-term increasing trend in global air and ocean temperatures also contributes to influences upon Australia's climate.


Areal average temperatures
Maximum Temperature Minimum Temperature Mean Temperature
Rank
(of 108)
Anomaly
(°C)
Comment Rank
(of 108)
Anomaly
(°C)
Comment Rank
(of 108)
Anomaly
(°C)
Comment
Australia 99 +1.32 10th highest = 99 +0.93 equal 9th highest 103 +1.13 6th highest
Queensland = 94 +1.04 99 +1.02 10th highest 99 +1.03 10th highest
New South Wales 97 +2.07 = 103 +1.28 equal 5th highest 101 +1.68 8th highest
Victoria 103 +2.12 6th highest = 104 +1.16 equal 4th highest (record +1.47 °C in 2009) 105 +1.65 4th highest (record +2.04 °C in 2015)
Tasmania 107 +1.62 2nd highest (record +1.89 °C in 1914) 100 +0.63 9th highest 108 +1.13 highest (was +1.03 °C in 2005)
South Australia 95 +1.47 100 +1.24 9th highest 98 +1.36
Western Australia 99 +1.31 10th highest 103 +0.94 6th highest 103 +1.12 6th highest
Northern Territory 93 +1.00 74 +0.29 = 82 +0.65

Rank ranges from 1 (lowest) to 108 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. 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
Mean
daily
temperatures
Map of mean daily temperature Map of mean daily temperature anomalies Map of mean daily temperature deciles

Rainfall

Spring rainfall was above average overall. Rainfall for the season was above average for much of the Northern Territory, the northwestern half of South Australia, large areas of Western Australia covering the Gascoyne, Interior and Kimberley, and large areas of northern and eastern Queensland. The season was drier than average for much of Tasmania, particularly in the east, the eastern half of Victoria, parts of eastern New South Wales, and parts of South Australia between the northern Eyre Peninsula and the Fleurieu Peninsula.

However, rainfall varied significantly across the season and for different parts of Australia in the individual months September to November.

September was an exceptionally dry month for South Australia, Victoria, New South Wales, and Queensland. Rainfall was in the lowest 10% of historical observations (decile 1) for September in central to southeastern Queensland, across most of New South Wales, parts of northern Victoria, and in South Australia's northern agricultural and southern pastoral districts. For New South Wales and the Murray-Darling Basin as a whole September rainfall was the lowest on record (since at least 1900).

Very much above average rainfall for the month of October was observed across much of eastern Queensland, and parts of southwestern Queensland and northern New South Wales. It was the wettest October on record for parts of the Wide Bay, Burnett and North Tropical Coast districts in Queensland with several heavy rainfall events during the month, resulting in flooding in some regions, particularly around Bundaberg from mid-October. This rainfall was primarily driven by enhanced easterly flow across warm ocean waters to the east of Australia (associated with a strong pulse of the Madden-Julian Oscillation (MJO) over the Maritime Continent), a mid-level trough situated along the northern and central Queensland coastline, and a region of high pressure over the Tasman Sea.

Unusual dry season rainfall was observed in Central Australia at the end of September, and in the Central Wheat Belt and Interior of Western Australia in mid-October. Totals were in excess of 50 mm at some locations for either month.

Parts of southern Victoria and much of Tasmania had observed below average rainfall for October, and saw a very dry month in November. A long-lived blocking high over the Tasman Sea during much of November saw persistently northerly airflow across much of southeastern Australia, with associated very much warmer than average daytime temperatures further exacerbating the effects of low rainfall.

November rainfall across large parts of Australia's interior was well above average, with parts of Central Australia seeing a particularly early start to their wet season.


Area-average rainfall
Rank
(of 118)
Average
(mm)
Departure
from mean
Comment
Australia 88 87.8 +21%
Queensland 97 116.3 +38%
New South Wales 52 106.7 −14%
Victoria 37 148.7 −18%
Tasmania 36 312.4 −14%
South Australia 102 74.5 +46%
Western Australia 93 53.1 +29%
Northern Territory 98 93.1 +38%
Murray-Darling Basin 57 102.8 −10%

Rank ranges from 1 (lowest) to 118 (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.


Rainfall maps
TotalsPercentagesDeciles
Total
rainfall
Map of total rainfall Map of percentage of normal rain Map of rainfall deciles


Australian weather extremes in spring 2017
Hottest day 45.1 °C    at Marble Bar (WA) on 22 November
Coldest day −3.9 °C    at Mount Hotham (Vic.) on 4 September
Coldest night −9.5 °C    at Perisher Valley Thredbo AWS (NSW) on 1 September
Warmest night 30.5 °C    at Bidyadanga (WA) on 20 October
Wettest day 389.0 mm at Makowata (Qld.) on 18 October


Notes

The Seasonal 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 1 pm EST on Friday 1 December 2017. 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 May 2009; the main effect was that current and historical values for Tasmania were increased. Since December 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.


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