Australia in October 2022

In brief

  • For Australia as a whole, October rainfall was the second-highest on record.
  • Rainfall was above or very much above average for most of Australia, and highest on record for large parts of the Murray–Darling Basin in New South Wales and Victoria. Rainfall was close to average or below average in the west of Western Australia and western Tasmania.
  • Area-averaged rainfall was the highest on record for October (compared with all Octobers since 1900) for New South Wales and Victoria, and amongst the ten highest for Queensland, South Australia, and Western Australia.
  • Significant flooding affected large areas of eastern Australia across October, in some areas over prolonged periods, or in multiple events.
  • Australia's national area-average mean temperature was 0.19 °C above average for October.
  • Area-average mean maximum temperature for October was 0.58 °C below average nationally, while the mean minimum temperature was 0.95 °C above average.
  • Mean maximum temperatures were above to very much above average for the northern tropics, and below or very much below average for most of the remainder of the mainland.
  • Mean minimum temperatures were above or very much above average for the tropics and the eastern half of Australia, but below average for large parts of Western Australia.

Further discussion and tables of records for each state and the Northern Territory can be found in the individual regional climate summaries, to be released on 4 November 2022.

Temperatures

The national mean temperature for October was 0.19 °C warmer than the 1961–1990 average for Australia as a whole, the coolest October since 2016.

Area-average mean maximum temperature for October was 0.58 °C below average nationally, the lowest since 2010, while the mean minimum temperature was 0.95 °C above average.

The mean maximum temperature for October was above or very much above average across the northern tropics from the tip of the Kimberley in Western Australia, through the north of the Northern Territory, and across Cape York Peninsula and Queensland's northern tropical coast. Mean maxima for October were below average for most of Western Australia, South Australia, New South Wales, southern Queensland, and northern and north-western Victoria.

Mean minimum temperatures were above or very much above average for much of the Kimberley; the northern and eastern halves of the Northern Territory; nearly all of Queensland, New South Wales, Victoria, and Tasmania; southern and far north-eastern South Australia; and far south-eastern Western Australia. Mean minimum temperatures were below average for most of the South West Land Division in Western Australia, extending across the inland north-west, northern Interior District, and into the south-west Northern Territory.

Mean minimum temperature was the second-warmest on record for Victoria, and amongst the ten highest on record for October (national records began in 1910) for Queensland, New South Wales, and the Northern Territory.

Diurnal temperature range (the difference between daily maximum and minimum temperatures) was lowest on record for New South Wales and fourth-lowest for Victoria. During very wet periods increased cloud cover, high humidity, and saturated soils commonly lead to a low diurnal temperature range, with both lower daytime temperatures and warmer nights.

For the southern cool season as a whole (April to October), the mean minimum temperature was amongst the ten highest on record for Queensland, New South Wales, and Victoria, reflecting the very high rainfall across these states.

A large number of stations around the coast in the tropics, from Queensland to the Kimberley, had their highest mean minimum temperature on record for the month, and quite a few stations had their warmest October on record overall (mean temperature).

The latter part of the month was marked by a period of warm weather in the north, with daytime temperatures much warmer than average across parts of the far northern tropics, including periods of extreme heatwave conditions (see significant weather section).

In Western Australia, cool weather across the Kimberley and large parts of the Interior at the start of the month included some records for coolest October day on the 1st, while records for coolest October day were also set at some stations in the south at the end of the month. For the month as a whole, a large number of stations in Western Australia observed their lowest mean maximum temperature for at least 20 years.

Some stations in New South Wales, and a few in southern Queensland, observed their lowest mean maximum temperature on record for October, or for at least 20 years. A number of stations in New South Wales, Victoria, and south-east South Australia observed their highest mean minimum temperature on record for October.

1-month temperature table ending October 2022
Areal average temperatures
  Maximum Temperature Minimum Temperature Mean Temperature
  Rank
(of 113)
Anomaly
(°C)
Comment Rank
(of 113)
Anomaly
(°C)
Comment Rank
(of 113)
Anomaly
(°C)
Comment
Australia 36 −0.58   97 +0.95   70 +0.19  
Queensland = 55 +0.28   107 +2.00 7th highest = 93 +1.14  
New South Wales 15 −1.53   104 +1.58 10th highest 60 +0.03  
Victoria 25 −1.06   112 +1.80 2nd highest (record +2.47 °C in 2015) 71 +0.37  
Tasmania 73 +0.36   103 +0.65   95 +0.51  
South Australia 22 −1.58   92 +1.03   50 −0.27  
Western Australia 25 −1.07   45 −0.38   35 −0.72  
Northern Territory = 78 +0.61   104 +1.51 10th highest 93 +1.06  

Rank ranges from 1 (lowest) to 113 (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 the second-highest on record for Australia as a whole, with the national area-average 158% above the 1961–1990 average (i.e. more than two and a half times the average).

October rainfall was below average for only small areas, in parts of west coast Western Australia and an area of western Tasmania, and close to average across the west of Western Australia.

Rainfall was above or very much above average for most of Australia, and in the highest 10% of all Octobers since 1900 over the east of Western Australia and parts of Western Australia's south coast; most of South Australia, Victoria, New South Wales; southern and parts of eastern and inland northern Queensland; and northern and eastern Tasmania. Rainfall was highest on record for October for large parts of the Murray–Darling Basin in New South Wales and Victoria.

Area-averaged rainfall was amongst the ten highest on record for October (compared with all Octobers since 1900) for Queensland, South Australia, and Western Australia. For New South Wales and the Murray–Darling Basin as a whole, area-averaged rainfall was the highest on record for all periods ending October ranging from 1 to 4 months long. Area-average rainfall for Victoria was the highest for any month since 1900, exceeding the previous record set in October 1975.

A very large number of stations in New South Wales and Victoria had their wettest October on record; as did a large number in South Australia, mainly in the south-east and south-eastern pastoral areas; a large number in northern and eastern Tasmania; a number in south-coast Western Australia and the Kimberley; and a number in Queensland. Nationally, on the order of 180 stations with at least 30 years of observations set records for highest total rainfall for October, and some 30 of those were highest for any month of the year.

 

Significant weather and records

Significant flooding affecting large areas of eastern Australia across the month

Flooding occurred from the first week of October as rain fell onto already wet soils and full or close to full catchments. In many parts of the Murray–Darling Basin the flooding occurred over prolonged periods, or on multiple occasions.

Throughout the month a number of low pressure systems or surface troughs crossed over southern or eastern Australia. These connected with tropical air masses from the north, which were laden with moisture drawn from exceptionally warm ocean waters. This combination led to storms and periods of prolonged, and at times very heavy, rainfall over the eastern states and parts of the interior.

A low pressure system south of the mainland linked up with tropical moisture from around the 12th, forming an extensive, slow-moving rain band over south-east Australia. Major flooding along the Maribyrnong River resulted in evacuations of inner Melbourne suburbs, while major flooding also led to inundation in a number of other cities and towns including Shepparton–Mooroopna, Rochester, and Echuca. A very large number of stations across central and northern Victoria and northern Tasmania set daily rainfall records for October during the 24 hours to 9am either on the 13th or the 14th. By the morning of the 17th, the Victorian State Emergency Service had received 3000 calls for help in 3 days and conducted 550 rescues in 5 days, with 4725 properties without power across the state.

Major flooding continued along multiple rivers in central and northern Victoria well into the following week, with the State Emergency Service issuing further evacuation orders in some places, and landslips contributing to road closures in addition to those obstructed by water.

A large number of stations in New South Wales, Victoria, an eastern South Australia set daily rainfall records for October between the 20th and 26th as a low pressure system developing over New South Wales was overtaken by a strong cold front crossing further south, bringing thunderstorms and moderate to heavy rainfall to large areas. These storms continued to affect parts of Victoria and south-east South Australia as a low pressure center reformed on a remnant trough behind the front, with the low then becoming slow moving over Tasmania.

On the 25th suburbs in Melbourne's outer east were hit by storms and flash flooding, with particularly intense rainfall observed in Lilydale and the surrounding area. Emergency services responded to 400 calls for help in just 90 minutes, with cars, businesses and homes damaged during the downpour.

Daily rainfall records for October were also observed in parts of northern Tasmania during the 24 hours to 9am on the 27th, as widespread showers and gusty winds returned to south-east Australia.

Storms in South Australia

A surface trough connected to low pressure system over the Great Australian Bight brought damaging easterly winds to Adelaide, the Mount Lofty Ranges, and Kangaroo Island on the 4th, with the State Emergency Service receiving almost 400 calls for assistance and leaving thousands without power.

Heavy rain in Queensland

A number of stations in Queensland across the Central Highlands and Central Lowlands set daily rainfall records for October between the 19th and the 22nd. A cut-off low and troughs crossing the continent produced thick middle- and upper-level cloud, bringing a moist airmass, widespread showers and embedded thunderstorms, and the risk of severe thunderstorms across much of Queensland.

Thunderstorms and high winds in late October in south-east Australia

High winds during the last days of the month saw gusts in excess of 100 km/h at multiple locations in South Australia and Victoria as a low pressure system and cold front crossed south-east Australia. In Victoria there were approximately 400 requests for assistance made to the State Emergency Service, mostly for trees down and associated damage.

Extreme heatwave conditions across the north

The latter part of the month was marked by a period of warm weather in the north, with daytime temperatures much warmer than average across parts of the far northern tropics from the 20th, particularly across the Top End and inland north of the Northern Territory from the 22nd, and on the eastern side of Cape York Peninsula from the 26th. Extreme heatwave conditions were observed over some parts of the tropics. For minimum temperatures, the 24th to the 28th, and the 31st were particularly warm. Some coastal stations from central coast Queensland, around the Gulf of Carpentaria, and in the Northern Territory set records for either their highest daily maximum or highest daily minimum temperature on record for October.

1-month rainfall table ending October 2022
Area-average rainfall
  Rank
(of 123)
Average
(mm)
Departure
from mean
Comment
Australia 122 60.1 +158% 2nd highest (record 67.3 mm in 1975)
Queensland 116 66.5 +158% 8th highest
New South Wales 123 142.1 +196% highest (was 109.5 mm in 1950)
Victoria 123 160.3 +148% highest (was 152.8 mm in 1975)
Tasmania 107 187.3 +58%  
South Australia 121 59.5 +227% 3rd highest (record 65.6 mm in 1975)
Western Australia 119 26.9 +134% 5th highest; highest since 2011
Northern Territory 111 40.2 +114%  
Murray-Darling Basin 123 138.5 +221% highest (was 102.0 mm in 1950)

Rank ranges from 1 (lowest) to 123 (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 2022
Hottest day 44.5 °C Wyndham Aero (WA) on the 24th
Coldest day 0.2 °C Thredbo AWS (NSW) on the 29th and 28th,
and Mount Baw Baw (Vic.) on the 9th
Coldest night −7.4 °C Perisher Valley AWS (NSW) on the 10th
Warmest night 31.0 °C Victoria River Downs (NT) on the 24th
Wettest day 288.2 mm Tin Can Bay (Defence) (Qld) on the 22nd

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