Tuesday 1 December 2020 — Seasonal Climate Summary for Australia — Product Code IDCKGC1A00

Australia in spring 2020

Temperatures Rainfall Extremes Important notes the top

In Brief

• Nationally, Australia's warmest spring on record; and amongst the six warmest springs on record for all states and the Northern Territory
• Mean maximum temperature and mean minimum temperature both warmer than average for virtually all of Australia
• Spring rainfall slightly below average for Australia as a whole
• Rainfall for the season was below average for much of eastern Queensland, north-eastern New South Wales, and western Tasmania
• Rainfall for spring above average for northern Western Australia, much of South Australia, western New South Wales, and south-west Victoria
• Longer-term rainfall deficits still persist in many parts of Australia

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Temperatures

Spring 2020 was the warmest on record for Australia, coming in with a mean temperature 2.03 °C above average, well above the previous record (+1.81 °C in 2014). The national mean maximum temperature was the fifth-warmest on record at 2.14 °C above average, while the mean minimum temperature was the warmest on record at 1.91 °C warmer than average (previous record 1.46 °C in 1998).

The mean temperature for spring was amongst the six highest on record for spring for all of the states and the Northern Territory.

Both the mean maximum and mean minimum temperature for the season were very much above average (decile 10, the highest 10% of historical observations) across the majority of Australia. Some parts of the northern tropics were analysed as having had their warmest spring on record for mean maximum temperature, while mean minimum temperature for the season was the highest on record for spring for areas of the inland northern tropics, south-western Queensland, the eastern half of Victoria and far south-east New South Wales, and much of the western half of South Australia.

Periods of unusually warm weather affected parts of Australia several times during spring. A number of stations in Western Australia observed record-warm September daily maximum or daily minimum temperatures during the first half of the month. The season closed with a significant heatwave affecting much of south-eastern and eastern Australia at the end of November when very warm air was pushed from the middle of the continent by frontal systems combined with a heat trough over inland Australia.

A large number of stations in New South Wales and South Australia observed record high November daily maximum temperatures on the 28th or 29th, as did a few stations in Victoria, while Queensland saw records on the 30th. A large number of stations in New South Wales also observed their warmest November night on record during the same period.

A number of stations in New South Wales, South Australia, Queensland, and Victoria observed their highest spring mean daily minimum temperature on record.

Temperature maps
	Mean	Anomaly	Deciles
Mean daily maximum temperatures
Mean daily minimum temperatures
Mean daily temperatures

Temperatures Rainfall Extremes Important notes the top

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Rainfall

Rainfall for spring was 8% below average for Australia as a whole.

Rainfall for the season was below average for greater south-east Queensland, extending to the north tropical coast, and into north-eastern New South Wales. Rainfall for spring was also below average for western Tasmania.

Rainfall for spring was above average for much of the Kimberley and Pilbara in Western Australia, much of South Australia except the south-east, western New South Wales and adjacent far south-west Queensland, and scattered smaller areas in south-west Victoria, south-east New South Wales, and southern Western Australia.

September was a drier than average month for some areas in the south-east and south-west of Australia, but above average for much of the central third of the country and west of the eastern states. October was a much wetter month as the La Niña strengthened in the tropical Pacific Ocean, although monthly rainfall was still below average for south-west Western Australia. November was drier than average for much of the eastern two thirds of Australia, but wetter than average for large parts of Western Australia.

Typically La Niña would be associated with cooler, cloudier, and wetter than average conditions for Australia. During November the La Niña currently active in the Pacific Ocean weakened temporarily, and the Southern Annual Mode also briefly returned to neutral. This contributed to a reduction in cloud cover over Australia during the month, higher air pressure, and less rainfall than typical for a La Niña. Both La Niña and the Southern Annual Mode are expected to return to their October levels soon, and the climate outlooks expect cooler temperatures and more rainfall for summer 2020–21.

Climate change is also playing a role in the weather which Australia experiences. Long-term rainfall trends have seen April–October rainfall decline by around 16% over the southwest of Australia since 1970, and by around 12% in the southeast of Australia since the late 1990s. Australia's climate has also warmed on average by 1.44 ± 0.24 °C since national records began in 1910, leading to an increase in the frequency of extreme heat events.

Heavy rain at times resulted in some daily rainfall records. Record high daily spring rainfall was observed at some stations in South Australia during September, New South Wales during October, and Western Australia during November.

Area-average rainfall
	Rank (of 121)	Average (mm)	Departure from mean	Comment
Australia	61	67.5	−6%
Queensland	44	60.6	−28%
New South Wales	68	121.4	−5%
Victoria	61	172.4	−5%
Tasmania	35	304.2	−14%
South Australia	98	70.4	+38%
Western Australia	76	40.1	+1%
Northern Territory	66	63.4	−5%
Murray-Darling Basin	55	103.7	−12%

Rank ranges from 1 (lowest) to 120 (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
	Totals	Percentages	Deciles
Total rainfall

Temperatures Rainfall Extremes Important notes the top

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Australian weather extremes in spring 2020
Hottest day	48.0 °C	at Andamooka (SA) on 28 Novemberh
Coldest day	−3.4 °C	at Thredbo AWS (NSW) on 26 September
Coldest night	−8.1 °C	at Thredbo AWS (NSW) on 26 September and Perisher Valley AWS (NSW) on 1 September
Warmest night	33.8 °C	at Wanaaring (Delta AWS) (NSW) on 29 November
Wettest day	209.8 mm	at Smiths Lake (Patsys Flat Road) (NSW) on 27 October

Temperatures Rainfall Extremes Important notes the top

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