Two maps 12 months apart show how different Australia’s weather has been this year after parts of the east coast were ravaged by bushfires last summer.
The Currowan fire in Shoalhaven, on the NSW South Coast, burnt through almost 500,000 hectares over more than two months.
South Australia’s picturesque Kangaroo Island was scorched by flames too, while some parts of northern NSW were also caught up in blazes.
But as ABC meteorologist Graham Creed pointed out, 2020’s weather has seen a marked change from what Australia saw 12 months ago.
He used two Bureau of Meteorology weather maps to compare December 2019 to December 2020, showing the contrast in the amount of rain that fell 12 months apart.
“Not all things in 2020 were bad,” he tweeted, possibly referencing the Covid-19 pandemic.
In Sydney during December 2019, only 2mm of rail fell in the entire month. In December 2020 a healthy 119mm had fallen as of the 29th – and many regions outside the city have received much higher rainfall totals.
‘Definitely a wetter December’
Weatherzone meteorologist Esteban Abellan told Yahoo News the wetter December in 2020 is due to the Indian Ocean Dipole (IOD) which has gone from positive to neutral. The IOD is a key driver in Australia’s climate.
“The positive phase drove conditions which led to bushfires,” Mr Abellan said.
“But this summer it's neutral.”
Not all things in 2020 were bad. This La Nina December with only a few days to go compared to Dec 2019 pic.twitter.com/jiOEPTEHzP
— Graham Creed (@WeathermanABC) December 29, 2020
When it’s in a positive phase, it results in less rainfall and higher than normal temperatures.
With the IOD now neutral, taking away the driver’s effect in negating rainfall, La Nina is bringing increased rainfall.
Sydney’s dramatic rainfall increase
December might not be over yet but so far Sydney has accumulated far more rain this month than it did last year.
Mr Abellan confirmed in 2019 Sydney received just 1.8mm across the entire month. On average, it’s meant to receive 80mm in December.
“Sydney has already picked up 120mm this month,” Mr Abellan said.
“Last year it was 0.2mm on one day and 1.6mm on another which was the 25th.”
Mr Abellan added on average December is meant to see Sydney have 12 days of rain.
But last year it had only two.
“We have had 18 days of rain so far,” he said.
More clouds, less sunlight
While the rainfall might be a relief to many after much of NSW was hit by drought last year the increased cloud cover has led to less direct sunlight.
“The number of hours of sunshine have been really low this December,” Mr Abellan said.
“The average hours of sunshine daily in NSW over December is 7.9 hours while currently we are experiencing 6.1 hours.”
“This is due to rain and low clouds.”
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