Australia in October 2021

In brief

  • Mean maximum temperatures for October were warmer than average for northern Australia, and warmest on record for some areas; cooler than average for the south-west of Western Australia
  • Mean minimum temperatures for October were warmer than average for Queensland and most of the Northern Territory, and for Tasmania; cooler than average for the inland south-east and the agricultural districts of South Australia, and in Western Australia in the South West Land Division, the Kimberley, and the northern Interior
  • October rainfall was 8% above average for Australia as a whole
  • However, geographically, rainfall was mixed
    • Rainfall was below average for parts of the Interior District in Western Australia and surrounding border regions, spots of the Kimberley coast, the north-east coastal strip of Queensland, and small pockets of inland eastern Australia
    • Rainfall was above or very much above average for the South West Land Division and much of the Gascoyne, southern Kimberley, and western Pilbara in Western Australia, around the Gulf of Carpentaria and the NT, western Queensland, along parts of coastal southern and eastern Australia, and across most of Tasmania except the west coast
  • For the southern cool season (April–October), rainfall was above average for much of the South West Land Division in Western Australia, parts of western to south-eastern Tasmania, and across Gippsland in Victoria and far south-east and northern inland New South Wales
  • Conversely, cool season rainfall was below average for the east of Western Australia, most of South Australia, and north-western Victoria and western New South Wales

Temperatures

The national mean temperature for October was 0.93 °C warmer than the 1961–1990 average for Australia as a whole. The mean maximum temperature for October was 1.09 °C warmer than average and the mean minimum temperature was 0.77 °C warmer than average.

Mean maximum temperatures for October were very much warmer than average (amongst the highest 10% of historical observations for the month) for much of northern Australia, and warmest on record for parts of the coast from the Kimberley to Queensland's Central Coast. The October mean maximum temperature was amongst the five warmest on record for the Northern Territory and Queensland. Mean maximum temperatures for October were cooler than average for the south-west of Western Australia.

Mean minimum temperatures for October were warmer than average for Queensland and most of the Northern Territory, and for Tasmania. They were warmest on record for most of the Top End and around the southern Gulf coast in the Northern Territory. Mean minimum temperatures for October were cooler than average for inland New South Wales, northern and western Victoria, the agricultural districts of South Australia, and in Western Australia in the South West Land Division, the Kimberley, and the northern Interior.

Warmth was persistent across the north, continuing record heat which had built from late September. Severe to extreme heatwave conditions affected the Kimberley and Top End during the month. A large number of stations in the Northern Territory and western Queensland set early season temperature records for the warmest day so early after mid-winter, while others observed record runs of consecutive days of high temperatures, including 23 consecutive days of 40.0 °C or above at Argyle Aerodrome in the Kimberley. Three consecutive days of at least 42.0 °C were reported at Tennant Creek Airport, each exceeding the previous highest October maximum temperature record of 41.9 °C. Victoria River Downs reached the second highest October temperature observed in the Northern Territory, with 44.9 °C on the 21st.

Frontal systems brought cold outbreaks to the south several times during the month. Between the 6th and the 12th a strong high pressure system brought cool, calm nights, followed by a series of cold fronts, with low temperatures bringing some records for lowest October daily minimum temperature for some stations along the southern coastline.

Further discussion and tables of records for each state and the Northern Territory can be found in the individual regional climate summaries, which will be published on November 4th.

 

1-month temperature table ending October 2021
Areal average temperatures
  Maximum Temperature Minimum Temperature Mean Temperature
  Rank
(of 112)
Anomaly
(°C)
Comment Rank
(of 112)
Anomaly
(°C)
Comment Rank
(of 112)
Anomaly
(°C)
Comment
Australia = 92 +1.09   = 90 +0.77   94 +0.93  
Queensland 108 +2.19 5th highest = 107 +2.04 equal 5th highest 109 +2.12 4th highest (record +2.74 °C in 1988)
New South Wales = 57 +0.22   62 −0.06   = 61 +0.08  
Victoria 45 −0.43   = 54 −0.10   49 −0.26  
Tasmania 58 −0.10   107 +0.99 6th highest = 92 +0.45  
South Australia 75 +0.63   = 75 +0.30   77 +0.47  
Western Australia 69 +0.44   51 −0.29   61 +0.08  
Northern Territory 106 +2.07 7th highest 107 +2.14 6th highest 110 +2.11 3rd highest (record +2.51 °C in 1988)

Rank ranges from 1 (lowest) to 112 (highest). A rank marked with ’=‘ indicates the value is tied for that rank. Anomaly is the departure from the long-term (1961–1990) average.

Rainfall

October rainfall was 8% above average for Australia as a whole, however, geographically, rainfall was mixed.

Rainfall was below average for parts of the Kimberley and much of the Interior District in Western Australia, north-west South Australia, the south-west of the Northern Territory, and through parts of inland eastern Australia in Queensland and New South Wales.

Rainfall was above or very much above average for the South West Land Division, southern Kimberley and western Pilbara in Western Australia the Northern Territory western Queensland, along parts of the east coast in mainland Australia, and across most of Tasmania except the west coast.

A number of stations along the west coast of Western Australia and the east coast of Tasmania observed record-high total monthly rainfall for October.

Thunderstorms were a frequent occurrence during the month, with severe storms and giant hail reported in parts of Queensland and New South Wales at various times. Several tornados were reported including at Armidale on the 14th, Mackay on the 20th, Brisbane on the 21st. This follows tornados at Clear Creek and Meadow Flat near Bathurst; near Narrabri; and near Mudgee, all during the afternoon of 30 September.

Large accumulations of small hail were observed across north-west Victoria on the 14th, with large to giant hail reported in parts of eastern New South Wales and south-east Queensland.

Giant to gargantuan hail was reported in Yalboroo (between Proserpine and Mackay in Queensland) on the 19th, with a hailstone measured at 16 cm, the largest hailstone measurement verified in Australia.

Giant hail up to 11 cm in diameter was reported around the Mackay area on the 20th, while severe thunderstorms brought heavy rainfall and large accumulations of small hail, forming into drifts, around Coffs Harbour in New South Wales.

An intense low pressure system crossing the central Bass Strait in the last days of the month brought severe weather to parts of western, northern, and southern Victoria, with large hail, damaging wind gusts, and localised heavy rainfall leading to flash flooding. Damaging winds developed overnight with significant impacts for southern Victoria, with numerous locations recording gusts in excess of 100 km/h, and some bayside areas experiencing a rapid storm surge.

Further discussion and tables of records for each state and the Northern Territory can be found in the individual regional climate summaries, which will be published on November 4th.

 

Cool season rainfall for southern Australia

For the southern cool season, April–October rainfall was above average for much of the South West Land Division in Western Australia, parts of western to south-eastern Tasmania, and across Gippsland in Victoria and far south-east New South Wales. Conversely, cool season rainfall was below average for the east of Western Australia, most of South Australia, and north-western Victoria.

Cool season rainfall was 13% below average for southern Australia as a whole (i.e. the area of Australia south of 26°S, which demarcates the northern border of South Australia).

Parts of south-west, south-east, and eastern Australia—including parts of south-east Queensland and southern and eastern New South Wales—have seen substantial declines in cool-season (April to October) rainfall in recent decades. The role of climate change in rainfall reduction over southern Australia and along the Great Dividing Range is discussed in State of the Climate 2020.

 

1-month rainfall table ending October 2021
Area-average rainfall
  Rank
(of 122)
Average
(mm)
Departure
from mean
Comment
Australia 83 25.2 +8%  
Queensland 82 29.1 +13%  
New South Wales 59 39.2 −19%  
Victoria 77 71.4 +10%  
Tasmania 113 200.7 +69% 10th highest
South Australia 62 13.1 −28%  
Western Australia 94 14.1 +22%  
Northern Territory 94 25.0 +34%  
Murray-Darling Basin 57 34.4 −20%  

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.

Australian weather extremes during October 2021
Hottest day 45.1°C Wyndham Aero (WA) on the 21st
Coldest day -0.8°C Thredbo AWS (NSW) on the 5th
Coldest night -7.8°C Perisher Valley AWS (NSW) on the 31st
Warmest night 30.1°C Lajamanu Airport (NT) on the 20th
Wettest day 182.2 mm Gray (Dalmayne Rd) (Tas.) on the 15th

Climate