Sydney’s autumn heatwave could be due to shift out of La Nina

The reason for parts of Australia being hit with a cool summer and warm autumn has been explained by an expert.

The ending of La Nina may have led to parts of Australia experiencing a warmer autumn than summer.

Sydney’s average temperature for March was its highest for the period in 165 years and other towns across New South Wales and the ACT also scorching though the month.

Weatherzone meteorologist Ben Domensino said the preceding “mild summer” made the March statistics “even more impressive”.

“What makes Sydney’s March heat even more impressive is that it followed a relatively mild summer,” he said.

“Based on daytime temperatures, March was hotter than December, January and February, which has only happened five other times in records dating back to 1859.”

Parts of Australian were hit with an autumn heatwave. Picture: NCA NewsWire/Tertius Pickard

Mr Domensino said it was also the city’s driest March in 13 years.

“Sydney’s Observatory Hill weather station received just 54 mm of rain this month, well below the long-term average of 132 mm,” he said.

Meanwhile, climatologist Hugh McDowell from the Bureau of Meteorology said the recent upturn in temperatures was a once in a century event.

“It’s quite a significant marker to see a March maximum temperature above anything we’ve seen in the past 100 years,” Mr McDowell told the ABC.

Other parts of Australia were also hit with high temperatures during the month but a rain filled week meant few other heat records were broken.

Mr McDowell went on to say a weather “rebound” could be the reason behind the late heat surge.

Sydney had its coolest summer in 11 years. Picture: NCA Newswire / Gaye Gerard

“It’s not unusual to see the dial swing the other way,” he said.

“This [year] has been unusual because we’ve had a La Niña and then La Niña has started to end sooner than you’d usually see.

“And that’s made a big difference. We normally don’t see any breaking down until into the winter.”

The latest summer was the coolest NSW has had in 11 years.

However, March brought Sydney’s daily highs up to 29C, compared to the long-term average of 24.8C.

Originally published as Sydney’s autumn heatwave could be due to shift out of La Nina