BOM’s senior climatologist Dr Simon Grainger said 2023 had been a mix of climate conditions,with record-high ocean temperatures since April acting as another major influence on our weather.
“As the oceans warm,that can also heat the area above it and make it more volatile,and means there is more moisture in the atmosphere,” Grainger said. “It’s played a pretty big role in the global climate by heating the atmosphere and changing atmospheric patterns.”
While it may seem like a sudden switch from La Nina to El Nino,Grainger said it’s fairly common. What will be of interest is the sort of pattern Australia gets next year – but more on that later.
We’ve also witnessed the lowest Antarctic sea ice extent since records began.
This year has also been the hottest on record globally,according to theCopernicus Climate Change Service. Every month since June has been the warmest on record.
Snapshot of the cities
Sydney has had a year of extremes,including cold nights and soaring daytime temperatures. The city recorded the driest year in four years,receiving only 970 millimetres of rain – 20 per cent below the annual average of 1223 millimetres.
Sydney’s wettest month was January,with 191 millimetres recorded. Interestingly,this is when the La Nina event was still active,though winding down.
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The harbour city received the lowest annual rainfall since 2019,and less than 40 per cent of 2022’s record annual total of 2530 millimetres.
The January to November average maximum temperature was 23.4 degrees,which is 0.8 degrees above the 1991–2020 average,and the fourth-warmest on record over all years since 1859.
If you felt nighttime temperatures this year were cooler,you’d be right. The January to November average minimum was 14.2 degrees,some 0.2 degrees below the 1991–2020 average.
Meanwhile,Melbourne had its driest year since 2019 with 555 millimetres of rain,6 per cent below the annual average. The wettest month for 2023 was April when 108 millimetres fell.
The city recorded just 10 millimetres of rain in September – the driest September since records began and more than 80 per cent below the monthly average. The previous record of 12 millimetres was set in 2008.
Melbourne’s January to November average maximum temperature was 19 degrees,0.2 degrees below usual. Despite the cooler conditions,September was the equal warmest on record to 2013,with 20 degrees.
Unlike Sydney,Melbourne’s nighttime minimum temperature was 0.2 degrees warmer than average,with the January to November average minimum reaching 11.6 degrees. It was the equal second-warmest winter night on record at 8.7 degrees,just 0.1 degrees behind 2001.
While it will be a few more weeks before the Bureau of Meteorology releases its 2023 summary,the agency has crunched the numbers for the past financial year. During that period,Australia’s national mean temperature was 0.13 degrees warmer than the 1961–1990 average. Partly responsible was the looming El Nino and the underlying effects of climate change.
Looking ahead
It’s still too early to tell what next year holds. Despite recent heavy rain in parts of NSW and Victoria,El Nino’s hot and dry conditions are expected to linger well into next year. However,Queensland and the north-east of NSW will likely see above-average rainfall from January.
Grainger said whatever Australia experiences next year will be amid a backdrop of global record heat temperatures,which will continue to make our weather more extreme and intense.
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