Australia Swelters Through Hottest Month On Record, With January Mean Temperature Exceeding 30c

ABC

Some states also experienced their driest January on record. (ABC News: Andrew O'Connor)

Key points There was less than 20 per cent of normal rainfall for large areas of Australia Canberra Airport had a record run of four days above 40C BOM senior climatologist Andrew Watkins said last month's heat was unprecedented

January 2019 was Australia's hottest month since records began in 1910, data to be released by the Bureau of Meteorology (BOM) today will show.
It followed the hottest December on record for Australia and there is no relief in sight for the months ahead.
January had the highest minimum, the highest maximum and the highest mean temperatures for Australia as a whole.
The mean temperature for January averaged across the country exceeded 30 degrees Celsius — the first time this had occurred in any month, the BOM said.
Rainfall was also below average for most areas but a monsoon trough brought some significant totals to northern Queensland late in the month.

Here is how the different states felt the heat

• South Australia experienced its driest January since 2013.
  And Adelaide had one of the city's hottest Januarys on record, with maximum temperatures the highest for at least 10 years.
  For the first time since 1957, the BOM's Adelaide city site recorded zero rainfall for the month.
• Western Australia had one of its hottest Januarys on record, but temperatures were cooler than average in parts of the west coast and south-west.
  Rainfall for the state was below average and the month was the driest since 2005.
  While most of WA was suffering in the heat, Perth recorded its coolest January in more than a decade and rainfall was about average.

The sun sets over Sydney in the midst of a heatwave. (ABC News: Mary Lloyd)

• New South Wales recorded its hottest January on record for mean, maximum, and minimum temperatures.
  The north-east of the state also experienced one of its driest Januarys on record.
  Sydney had one of its warmest Januarys on record, with average rainfall.
• Victoria also set a new record for January heat.
  Its rainfall was below average, with most of the state receiving less than 20 per cent of the month's average.
  Melbourne was exceptionally warm, with some sites recording their highest ever January temperatures.
  The city also had one of the 10 driest Januarys on record.
• The ACT also had its hottest January ever.
  The BOM's Canberra airport site had a record run of four days above 40C.
• The Northern Territory recorded its hottest January and the delayed onset of the monsoon contributed to the Territory receiving less than half its average January rainfall.
  Darwin had one of its warmest Januarys on record while rainfall was also below average.
• Queensland similarly had its hottest January and a monsoon low brought heavy rainfall to parts of the state.
  Brisbane was very warm, while rainfall was very low at about 20 per cent of the January average.
• Tasmania had its hottest and driest January on record, as did Hobart.

Why so hot?

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The predicted El Nino did not eventuate this summer but even without the climate driver we usually associate with hot conditions the temperatures soared.
BOM senior climatologist Andrew Watkins said there were a few factors at play in the unprecedented heat.
"We saw heatwave conditions affect large parts of the country through most of the month, with records broken for both duration and also individual daily extremes," Dr Watkins said
"The main contributor to this heat was a persistent high-pressure system in the Tasman sea which was blocking any cold fronts and cooler air from impacting the south of the country.
"The warming trend, which has seen Australian temperatures increase by more than one degree in the last 100 years, also contributed to the unusually warm conditions."

Australian mean temperature 1910 to 2017

What have the impacts been?

The stand-out events this month were the record-breaking heatwaves over the south-east of Australia. Andrew Gissing, of catastrophe modelling provider Risk Frontiers, said there were anecdotal reports of businesses suffering from blackouts leading to financial loss.
He said there were also reports of agricultural production being affected.

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Be prepared for the heat

Heatwaves kill far more people than other natural disasters. ABC Emergency has a checklist of things you can do to be ready.

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"Things like on really hot days milk production goes down because the cows suffer from heat stress as well," he said.
"We are seeing reports from the viticulture industry too about grapes being sunburned and shrivelling."
Then there are the human impacts.
So far it has been too soon to say how the heatwaves have affected people's health.
But Mr Gissing's research has shown that historically heatwaves are Australia's biggest killer in terms of natural hazards.
"In fact they are bigger than the sum total of all other fatalities from natural hazards put together," he said.
It is the elderly, those with chronic health conditions and the very young who are most at risk.

Is there an end in sight?

Both days and nights are highly likely to be above average over the next few months. (Supplied: Bureau of Meteorology )

No, there is not.
The outlook for the next three months suggests temperatures are very likely to be warmer than average for the majority of Australia.
The country will likely be drier than average, particularly in the west, and low to near-median stream flows are expected.

Links

• Bureau of Meteorology: Australia experiences its hottest January on record
• 2018 was Australia's third-hottest year on record
• The stubborn high-pressure system behind Australia's record heatwaves
• January was Australia's hottest month since records began
• 'Exceptionally hot, exceptionally dry': January was Australia's hottest month on record 
• Where is the monsoon?