Australia in autumn 2018

In Brief

  • An exceptionally warm autumn for Australia; nationally the fourth-warmest autumn on record
  • Maxima and minima both above average, and days exceptionally warm for large areas and for Australia as a whole
  • National monthly mean maximum temperature for autumn fourth-warmest on record for autumn
  • Only Queensland, the Northern Territory, and Tasmania rank outside the top ten for autumn mean maximum temperature
  • Autumn rainfall totals were below average for most of Australia, and very much below average across the southern mainland
  • Rainfall was above average between the southeast of the Northern Territory and Queensland's North Tropical Coast, due to above to very much above average rainfall during March

Temperatures

Autumn was exceptionally warm for Australia. All regions except Tasmania, Queensland, 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 fourth-warmest autumn on record (1.18 °C above the long-term average). Both maximum and minimum temperatures were warmer than average for Australia, particularly maxima, which were the fourth-warmest on record for autumn (+1.74 °C). Minima ranked just outside the top ten, at 0.62 °C above the long-term average

Daytime temperatures for autumn were above average for nearly all of Australia, in the highest 10% of historical observations (decile 10) for most areas except for Tasmania and for Queensland away from the southern border. Mean monthly maxima were the warmest on record for much of New South Wales, including Sydney; parts of Victoria, particularly far eastern Victoria; and about Northwestern Cape in Western Australia.

Mean minimum temperatures were above to very much above average for the majority of Australia. Minima were below average for most of the Kimberley in Western Australia and the southeastern Top End in the Northern Territory. Minima were near average for much of the remainder of the northeastern quarter of Western Australia, the southwest of the Northern Territory, parts of Queensland's east and Gulf Country, along the border of New South Wales and Victoria inland of the Great Dividing Range, and in areas along the south coast of Western Australia.

Each of the individual months of autumn was warmer than average nationally, although heavy rain and associated cloud cover led to below average maxima for March over much of northern Queensland, and mean monthly minima were cooler than average for a large area stretching from the Kimberley in Western Australia, through the south of the Northern Territory, into pastoral South Australia. April was an exceptionally warm month, with persistent abnormal warmth setting records for intensity, persistence, or both. Records set are discussed in a Special Climate Statement Persistent summer-like heat sets many April records.


Areal average temperatures
Maximum Temperature Minimum Temperature Mean Temperature
Rank
(of 109)
Anomaly
(°C)
Comment Rank
(of 109)
Anomaly
(°C)
Comment Rank
(of 109)
Anomaly
(°C)
Comment
Australia 106 +1.74 4th highest (record +2.17 °C in 2005) 95 +0.62 106 +1.18 4th highest (record +1.86 °C in 2016)
Queensland 91 +0.89 95 +0.81 98 +0.85
New South Wales 109 +2.66 highest (was +2.41 °C in 2016) 101 +1.10 9th highest 108 +1.88 2nd highest (record +2.21 °C in 2016)
Victoria 108 +1.74 2nd highest (record +1.83 °C in 2016) 91 +0.58 106 +1.17 4th highest (record +1.87 °C in 2016)
Tasmania = 87 +0.34 98 +0.68 = 94 +0.51
South Australia 107 +2.06 3rd highest (record +2.83 °C in 2005) 92 +0.76 102 +1.42 8th highest
Western Australia 108 +2.03 2nd highest (record +2.37 °C in 2005) 89 +0.50 105 +1.26 5th highest
Northern Territory 102 +1.55 8th highest 75 +0.18 92 +0.87

Rank ranges from 1 (lowest) to 109 (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

Autumn rainfall was below to very much below average for most of Australia. Rainfall for the season was in the lowest 10% of historical observations (decile 1) for much of the southern mainland; for southern Australia as a whole, autumn rainfall was the second-lowest on record. New South Wales, South Australia, and Western Australia all observed area-averaged autumn rainfall amongst the ten lowest on record for their respective States, with a number of stations in New South Wales and Western Australia receiving record-low rainfall for the season.

Rainfall was below average for most of the southern mainland in each month of autumn. April was the eighth-driest on record nationally, and May was the third-driest on record. A number of stations in Victoria, and New South Wales observed record-low monthly rainfall totals for April, followed by more record-low rainfall totals for May in New South Wales.

There is a consistency between low rainfall this autumn for southern Australia and climate change.

March rainfall was above to very much above average for much of the south of the Northern Territory, and western, central, and much of northern Queensland. Rain in these regions was largely the result of a tropical low in early March, and tropical cyclone Nora late in the month; some daily rainfall records were set in Queensland associated with each of these events. Tropical cyclone Marcus also affected the Top End and Western Australia during March, becoming the most intense tropical cyclone in the Australian region for more than a decade.

Southeastern Tasmania observed above average May rainfall, largely as a result of a single event when a complex low pressure system brought record-breaking rain overnight from the 10th to 11th, with significant flooding around Hobart.


Area-average rainfall
Rank
(of 119)
Average
(mm)
Departure
from mean
Comment
Australia 20 80.9 −33%
Queensland 88 174.2 +7%
New South Wales 8 56.5 −60% 8th lowest; lowest since 2005
Victoria 15 95.3 −39%
Tasmania 84 365.2 +7%
South Australia 11 19.3 −66%
Western Australia 7 34.3 −62% 7th lowest; lowest since 1994
Northern Territory 40 91.8 −34%
Murray-Darling Basin 8 47.4 −60% 8th lowest

Rank ranges from 1 (lowest) to 119 (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 autumn 2018
Hottest day 45.9 °C    at Roebourne Aero (WA) on the 28th and Mardie (WA) on 29 March
Coldest day −2.6 °C    at Mount Hotham (Vic.) on 10 May
Coldest night −6.7 °C    at Perisher Valley AWS (NSW.) on 25 May and Glen Innes Airport AWS (NSW) on the 31st
Warmest night 31.7 °C    at Wittenoom (WA) on 28 March
Wettest day 593.0 mm at Port Douglas - Warner St (Qld) on 26 March


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 June 2018. 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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