Tuesday 1 June 2021 — Seasonal Climate Summary for Australia — Product Code IDCKGC1A00

Australia in autumn 2021

Temperatures Rainfall Extremes Important notes the top

In Brief

• The national mean temperature for autumn was above average for Australia as a whole, but the coolest since 2015
• The mean maximum temperature was above average for Australia as a whole; warmer than average for the southern half of Western Australia, southern South Australia, much of northern Australia, and Tasmania; but cooler than average for central and northern New South Wales and adjacent southern Queensland
• The mean minimum temperature was below average for Australia as a whole; cooler than average for much of inland mainland south-eastern Australia, and also for the Kimberley and south-west of the Northern Territory; warmer than average for much of the remainder of Western Australia and for far northern Queensland
• Rainfall for autumn was slightly below average for Australia as a whole
• Rainfall for autumn above average for the west of Western Australia and the Kimberley, much of Central Australia, much of New South Wales, southern Queensland, and eastern Victoria
• Rainfall for the season was below average for much of the remainder of southern Australia, including northern Tasmania

---

Temperatures

The national mean temperature for autumn was 0.31 °C warmer than average for Australia as a whole, the coolest since 2015.

The mean maximum temperature was above average for autumn at +0.64 °C, the coolest since 2015. The mean minimum temperature was below average for autumn at −0.02 °C, the coolest since 2012. None of the states or territories ranked in the top or bottom 10 warmest or coolest for their respective autumn temperatures.

Mean maximum temperatures for autumn were above average for the southern half of Western Australia, many of the Agricultural districts of South Australia, Tasmania and much of northern Australia. Autumn mean maximum temperatures were below average for central and northern New South Wales and adjacent southern Queensland.

Mean minimum temperatures for autumn were average to very much above average for most of the southern half of Western Australia and parts of far northern Queensland. Autumn mean minimum temperatures were below average for the Kimberley and south-west of the Northern Territory, and for much of inland mainland south-eastern Australia. Mean minimum temperatures for inland New South Wales were 1 to 2 °C below average.

Cool days were observed across parts of south-eastern Australia between 14 and 17 March associated with the passage of a cold front and surface trough, and in Western Australia in the Kimberley and eastern Pilbara regions on 19 and 20 March. A few sites in New South Wales, Queensland and Western Australia had their coldest March day on record during this period.

At the end of March, the southern half of Western Australia saw low-intensity heatwave conditions across parts of the inland southern Gascoyne and eastern South West Land Division. Severe heatwave conditions were reached in the Southeast Coastal District. A small number of stations in Western Australia observed their warmest March night on record on 30 March. The warm conditions extended across southern Australia in early April. A number of sites in Western Australia and Tasmania recorded their highest April temperature on record during this period. As the hot air mass pushed northwards across eastern Australia a few sites in Queensland had their warmest April day on record on 10 or 11 April.

A succession of cold fronts crossed south-eastern Australia during mid-April. Snow fell in southern Alpine regions behind a cold front on 10 April, including flurries in the Dandenong Ranges to the east of Melbourne. A large number of sites had their coolest April temperatures for at least 10 years between 20 and 24 April. A number of sites in New South Wales and South Australia observed their lowest April temperature on record, and a few in Tasmania had their lowest April daily maximum temperature on 20 April.

May began with warm temperatures across the south-east, a number of sites in New South Wales, Victoria and Tasmania had their warmest May maximum temperature on record on 2 May, and a few sites in New South Wales and Victoria had the warmest May night during the first week of the month.

High pressure systems brought clear skies and settled weather at times in the second half of the month for much of eastern Australia. Minimum temperatures in parts of inland New South Wales were more than 4 °C below average from between 16 and 20 May and more than 10 °C below average in the Queensland southern interior on 17 May. Nights were colder still across the south-east between 29 and 31 May. Many sites in Victoria, New South Wales and south-east South Australia observed their coldest May night on record during that period.

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

Temperatures Rainfall Extremes Important notes the top

---

Rainfall

Rainfall for autumn was 3% below average for Australia as a whole.

Rainfall for autumn was above average for the west of Western Australia, the Kimberley and adjacent border regions of the Northern Territory; an area spanning the far south of the Northern Territory and northern South Australia; much of eastern Australia including most of New South Wales, southern Queensland and eastern Victoria.

Rainfall for the season was below average for the south-eastern quarter of Western Australia, southern and south-eastern South Australia, south-west New South Wales and western Victoria, and northern Tasmania. While March rainfall was above or very much above average for much of east Australia and the west of Western Australia, April and May rainfall was around 40% below average across southern Australia, contributing to emerging rainfall deficiencies in some areas.

During the second half of March a blocking high pressure system in the Tasman Sea and a low-pressure system off north-west Australia fed a large volume of moist, tropical air into eastern Australia. Heavy rainfall during 17 to 26 March extended from central Australia to northern inland New South Wales, leading to widespread significant flooding in most coastal catchments in New South Wales, and some adjacent parts of south-east Queensland and eastern Victoria. There was also significant flooding on some inland rivers in northern New South Wales and southern Queensland, as well as in eastern Tasmania.

A large number of sites in New South Wales observed daily rainfall records for autumn during this period, with a number going on to record their highest autumn total rainfall. Daily records were also set at some sites in Victoria, Tasmania and Queensland, including an isolated, extremely heavy daily rainfall total of 550.0 mm at Byfield Childs Road in the Capricornia District on 17 March. New South Wales had its second wettest March since national records began in 1900. The extreme multi-day rainfall and resulting flooding is further discussed in a Special Climate Statement.

Four tropical cyclones occurred within the Australian region during autumn 2021, with two affecting the mainland. Severe tropical cyclone Niran was offshore from Cairns, in far northern Queensland, on 1 and 2 March, but caused major flooding and extensive agricultural damage, particularly affecting banana crops. Severe tropical cyclone Seroja crossed the coast of Western Australia between Kalbarri and Geraldton during the evening of 11 April, bringing heavy rainfall and damaging winds to a broad area and causing significant infrastructure damage. Several sites in South West Western Australia had their highest April daily rainfall on record during this event.

Flooding occurred in catchments around Cairns from 19 April, which was the start of several consecutive days of 100 mm to 200 mm of rain at some sites and a 3-day total of 786.0 mm at Mt Sophia, and a 3-day (19 to 21 April) total of 539.2 mm at Cairns.

On 11 and 12 May a complex low and cold front brought widespread rainfall over south-east Australia, including locally heavier daily falls in excess of 100 mm in the South Coast District in New South Wales, and East Gippsland in Victoria. A number of sites in both states observed daily rainfall records for May in the 24 hours to 9 am 12 May.

Area-average rainfall
	Rank (of 122)	Average (mm)	Departure from mean	Comment
Australia	79	118.3	−3%
Queensland	= 62	144.8	−12%
New South Wales	102	178.2	+19%
Victoria	43	123.0	−23%
Tasmania	45	301.4	−10%
South Australia	68	46.0	−20%
Western Australia	83	105.2	+16%
Northern Territory	62	115.7	−19%
Murray-Darling Basin	= 89	123.8	−2%

Rank ranges from 1 (lowest) to 122 (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

---

Australian weather extremes in autumn 2021
Hottest day	43.0 °C	at Oodnadatta Airport (SA) on 2 March
Coldest day	−3.9 °C	at Mount Hotham (Vic.) on 15 May
Coldest night	−9.4 °C	at Perisher Valley AWS (NSW) on 16 May
Warmest night	30.1 °C	at Giles Meteorological Office (WA) on 5 March
Wettest day	550.0 mm	at Byfield Childs Road (Qld) on 17 March

Temperatures Rainfall Extremes Important notes the top

---

---

---