Australia in December 2022

In brief

  • For Australia as a whole, December rainfall was 33% above average.
  • The national rainfall average is composed of significant geographic differences between the tropics and the southern half of Australia.
  • Rainfall was above or very much above average for most of the Northern Territory, western Queensland and the Cape York Peninsula, the eastern half of the Kimberley and the Gascoyne in Western Australia.
  • Rainfall was below average for parts of the southern half of Australia, particularly in south-west Western Australia, eastern New South Wales, and western Tasmania.
  • Australia's national area-average mean temperature was 0.21 °C below average for December.
  • Area-average mean maximum temperature for December was 0.33 °C below average nationally. The national mean minimum temperature was 0.11 °C below average.
  • Both mean maximum and mean minimum temperatures were below or very much below average across much of the eastern mainland states, and above average for the north-west and northern coast of Western Australia, and some areas around the top of the Great Australian Bight and Top End coast.

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 5 January 2023.

Temperatures

The national mean temperature for December was 0.21 °C cooler than the 1961–1990 average for Australia.

Area-average mean maximum temperature for December was 0.33 °C below average nationally, while the mean minimum temperature was 0.11 °C below average.

The mean maximum temperature for December was below average across nearly all of New South Wales, far eastern Victoria, most of Queensland, across the central and southern Northern Territory and extending into the adjacent south-eastern Kimberley, and also on the south coast of Western Australia. The mean maximum temperature was in the lowest 10% of historical observations (compared with all Decembers since 1910) for much of New South Wales, mostly inland of the coastal ranges. The mean maximum temperature for the month was above average for western Tasmania, part of south-west South Australia, most of the north-western quadrant of Western Australia and much of the Kimberley coast, and also for pockets of the Top End.

Mean minimum temperatures were below or very much below average for northern Victoria, nearly all of New South Wales, most of Queensland except the west and Cape York Peninsula, and also for an area of north-western Australia extending from the Kimberley into adjacent parts of the Northern Territory. The mean minimum temperature was the lowest on record for December for a large area of north-eastern New South Wales, mostly inland of the coastal ranges, and in the lowest 10% of historical observations (compared with all Decembers since 1910) for much of central to eastern New South Wales and much of eastern Queensland. For New South Wales as a whole, the December mean minimum temperature was the equal-7th lowest on record, and the lowest since 1964.

The mean minimum temperature was above average for large areas of Western Australia covering the Pilbara, northern Gascoyne, the south-east and adjacent western South Australia. Small pockets in the coastal Kimberley, central Cape York Peninsula, and around the junction of the Northern Territory, Queensland, and South Australian borders also had warmer than average mean minimum temperatures.

A large number of stations in New South Wales and Queensland observed their lowest monthly mean minimum temperature on record for December, but mostly at stations with less than 50 years of observations. Some stations in New South Wales observed their lowest monthly averaged maximum temperature on record for December.

Cool conditions during the month also resulted in daily records being set across parts of greater south-eastern Australia during the month. See significant weather section and individual regional climate summaries (to be published on 5 January 2023) for more detail.

1-month temperature table ending December 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 = 48 −0.33   53 −0.11   54 −0.21  
Queensland 29 −0.73   36 −0.49   = 32 −0.60  
New South Wales = 12 −1.68   = 7 −1.71 equal 7th lowest; lowest since 1964 5 −1.69 5th lowest; lowest since 1964
Victoria 36 −0.44   = 52 −0.10   40 −0.26  
Tasmania 75 +0.79   = 61 −0.01   73 +0.39  
South Australia 63 +0.22   = 63 +0.34   62 +0.28  
Western Australia 81 +0.44   = 87 +0.39   84 +0.42  
Northern Territory 43 −0.87   61 +0.11   54 −0.37  

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

For Australia as a whole, December rainfall was 33% above the 1961–1990 average. However, this national average is composed of significant geographic differences between the tropics and the southern half of Australia.

Rainfall was above or very much above average for most of the Northern Territory, western Queensland and the Cape York Peninsula, the eastern half of the Kimberley and the Gascoyne in Western Australia. For the Northern Territory as a whole, December area-averaged rainfall was the 8th-highest on record (compared with all Decembers since 1900).

Rainfall was below average for parts of the southern half of Australia, including parts of south-west and inland southern Western Australia, eastern New South Wales and south-eastern Queensland, extending into the Central Highlands District, and western and northern Tasmania.

An active pulse of monsoonal activity towards the end of the month brought areas of embedded storms and tropical showers across parts of northern Australia, resulting in some observations of heavy rainfall. Daily rainfall records for December were set at a few stations in the Northern Territory and Western Australia in the Kimberley and Gascoyne at the end of the month. A small handful of stations observed record high rainfall totals for December as a whole in the Northern Territory and in Queensland's Cape York Peninsula.

  

Significant weather and records

Flooding continues on inland rivers in south-eastern Australia

Following extended periods of flooding during spring, major flooding continued as flood waters progressed through a number of inland rivers in the south-eastern mainland states and southern Queensland.

Extended periods of major flooding affected the Darling, Namoi, Barwon, Macquarie, and Murray–Darling rivers during December.

A Special Climate Statement on the ongoing floods is being prepared and will be published in due course.

Cold outbreaks over south-eastern Australia

During December there were two main periods during which cold outbreaks brought unusually low temperatures over south-eastern Australia, with a great many stations observing a record low daily minimum temperature for December during the month, with most records occurring between the 9th and the 16th. The highest number of stations setting records were located in New South Wales, but records were also observed in Victoria, South Australia, Tasmania, and southern Queensland.

On the 8th a cold front extended from a low over the Tasman Sea to the central coast of New South Wales. A southerly airstream behind the cold front brought temperatures up to 10 degrees cooler than average for December and areas of scattered low cloud along the coastal areas of Victoria, Tasmania, and New South Wales. Perisher Valley in the New South Wales Alps dropped to –7.0 °C on the morning of the 9th, equalling the Australian record for lowest temperature observed during December.

A second cold outbreak occurred over south-eastern Australia between the 12th and 16th brought daily minimum temperatures more than 8 degrees cooler than average across parts of Victoria, New South Wales, South Australia, and southern Queensland. A few stations in eastern Victoria and eastern Tasmania set records for lowest December daily maximum temperature on record, mostly on or around the 15th, but also including a daily minimum temperature of –5.4 °C on the 12th at Mount Hotham, the lowest temperature on record in Victoria during December.

Northern Australia heatwaves

Heatwave conditions affected large areas across northern Australia during the first half of December. Daily maximum temperatures were more than 6 degrees warmer than average across areas of the Northern Territory, western Queensland, north-west New South Wales, and outback South Australia, rising to more than 8 degrees above average in some parts of north-west Western Australia. On the 11th, Mandora reached 48.5 °C setting an all-time record for the site and early-season record for Western Australia. Severe to Extreme heatwave conditions affected multiple population centres such as Darwin (Northern Territory), Cairns (Queensland), and Broome (Western Australia).  

Hot end to the month for large parts of southern Australia

Heatwave warnings were issued for parts of Western Australia, South Australia, Victoria, and Tasmania between the 25th and 28th of December, with temperatures rising into the high 30s or low 40s across large areas. A few stations in south-east Australia set records on the 27th or 28th, mostly at exposed or higher-altitude stations. Minimum temperatures were particularly elevated, climbing some 8 to 16 degrees above average for December nights.  

Storms

  • Widespread storms produced copious lightning strikes across south-west Western Australia on the 7th, igniting eight fires
  • Intense thunderstorm activity brought reports of large to giant hail and locally destructive winds in parts of south-east and central eastern Queensland on the 8th
  • On the 12th storms in New South Wales resulted in the State Emergency Service responding to almost 300 requests for assistance, with high winds reported across large parts of the east of the state  

Tropical cyclone Ellie

Tropical cyclone Ellie was a Category 1 cyclone that crossed the western Top End coast early in the morning of the 23rd. Dropping to tropical low strength, the storm continued to produce heavy rainfall over central and northern parts of the Territory and parts of the Kimberley during the last part of December, with daily totals exceeding 100 mm at a number of locations. This heavy rainfall resulted in flooding of the Fitzroy River, with further heavy rain continuing into the start of January.

 

1-month rainfall table ending December 2022
Area-average rainfall
  Rank
(of 123)
Average
(mm)
Departure
from mean
Comment
Australia 91 67.4 +33%  
Queensland 85 96.6 +18%  
New South Wales 32 29.1 −42%  
Victoria 60 41.0 −14%  
Tasmania 25 64.9 −37%  
South Australia 70 17.0 −7%  
Western Australia 67 36.9 +26%  
Northern Territory 116 153.3 +109% 8th highest
Murray-Darling Basin = 33 27.7 −39%  

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 December 2022
Hottest day 48.5 °C Mandora (WA) on the 11th
Coldest day −0.2 °C Thredbo AWS (NSW) on the 14th
Coldest night −7.0 °C Perisher Valley AWS (NSW) on the 9th
Warmest night 34.3 °C Marble Bar (WA) on the 12th
Wettest day 208.0 mm Bradshaw Range Control (NT) on the 24th

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