A combination of moist ocean weather cycles, low-pressure systems and climate change have combined to make 2022 the wettest year ever recorded in Sydney
Environment
7 October 2022
Sydney has been drenched with unprecedented amounts of rain in 2022 MUHAMMAD FAROOQ/AFP via Getty Images
This year is already Sydney’s wettest year on record, with more than 2.2 metres of rain having fallen since January.
Previously, Sydney’s wettest year was 1950, when the total annual rainfall was 2.194 metres. This year’s rainfall topped that figure at around 1pm on 6 October.
In an average year, Sydney only gets about 1.2 metres of rain.
2022 has been a truly exceptional year of rainfall in #Sydney. It only took 279 days to break the city’s annual rainfall record of 2194mm from 1950, with annual data available back to 1859. pic.twitter.com/z6RtCopxqO
— Ben Domensino (@Ben_Domensino) October 6, 2022
With almost a quarter of the year left to go and wet conditions predicted to continue, 2022 is likely to be the wettest year on record in Sydney by a long margin, says Milton Speer at the University of Technology Sydney.
There are several reasons why it has been so wet, he says. One is that for the third year in a row, the east coast of Australia is experiencing a La Niña weather cycle, which attracts moist onshore winds from the Pacific Ocean.
Another is that there have been a series of low-pressure troughs associated with low-pressure systems that have “focused the rain for extended periods on Sydney and other parts of the coast”, says Speer.
Bit wet on no. 2 oval today at @Sydney_Uni #rain #imissthesun pic.twitter.com/RzFa3KkLC0
— Prof Simon de Graaf (@spdegraaf) October 6, 2022
In addition, a weather cycle called the Indian Ocean Dipole that affects countries around the Indian Ocean, including Australia, has recently moved into its negative phase, which is enhancing Sydney’s rainfall even further.
Finally, climate change may be exacerbating the wet conditions by raising sea surface temperatures so that there is more evaporation and more moisture in the air to fall out again as rain, says Speer.
The deluge has already caused repeated flooding in Sydney, particularly in areas near the Hawkesbury and Nepean rivers, where residents have been evacuated four times this year.
The flooding damaged homes, shops and infrastructure, and four people have drowned.
Heavy rain is set to continue in Sydney and other parts of the state of New South Wales over the coming days, with flood warnings in place for 50 locations.
50 current FLOOD warnings across NSW ☔
6th October at 6pmADVICE – 36
WATCH & ACT – 14
EMERGENCY WARNING – 0Monitor the latest warnings on the interactive map on our website: https://t.co/t578A4uJoA
For road closures and to plan your trip visit: https://t.co/PHnMnBFSBx pic.twitter.com/XY9iCOF1ZL— NSW SES (@NSWSES) October 6, 2022
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