Sydney breaks June temperature record amid unusual heatwave across Australia

Temperatures in Sydney topped 20C on Tuesday for the 10th consecutive day, breaking a record for June that had stood since 1919.

On another warm day in Sydney, the thermometer at Observatory Hill showed 20.1C by 11.30am on Tuesday. Usual maximum temperatures are about 18C.

That temperature recording – once checked by Bureau of Meteorology staff – will confirm a record for the city for the highest number of consecutive days above 20C for June – the first month of winter.

“It’s not unusual to get a day or two above 20C in June in Sydney but what’s unusual is to have them for this prolonged period,” said bureau spokesperson Casey McCarthy.

“My antennae went up pretty quickly once I saw we had three or four days.”

If forecasts for the coming days hold, McCarthy said Sydney could finish this warm spell with a record 14 consecutive June days above 20C.

Temperature records at Observatory Hill go back to 1859 and over that period the average daily maximum temperature for June has been 17C.

Maximum temperatures of 22C are forecast for Wednesday with 23C days likely in store for Thursday and Friday. Forecasters said the weekend temperature may reach 20C.

The unusual heat, McCarthy said, was down to an area of high pressure over the Tasman Sea to the east that pulled warmer air from the north while deflecting cooler fronts.

Sea surface temperatures of the New South Wales coast had also been slightly warmer than usual, helping bring moist air to the region “that’s more typical of autumn”, he said. Nights have also been unusually warm, he said.

Prof Andy Pitman, a climate scientist at the University of Sydney, said: “It’s been warm here and one of the challenges is most people will be enjoying it. I haven’t put the heating on in our house yet.

“But beating a longstanding record, not by a small amount, suggests something is changing. And that is CO2. There is a global warming factor here.”

He said the long-term ecological consequences of the kind of changes playing out were severe, including the country’s susceptibility to bushfires.

Unusual heat

The unusual heat has extended well beyond Sydney, with long runs of warmer than usual daily temperatures in Canberra, Melbourne, Adelaide and Hobart.

“This pattern is pretty consistent across most of south east Australia. Symbolic of that are the bare ski fields at the moment,” McCarthy said.

If forecasts are correct, Canberra will see 11 consecutive days above 15C when its average is about 12C.

Melbourne has seen eight days above 17C when the average is about 14C, Adelaide has gone through eight days above 17C and Hobart is looking at a nine-day stretch above 15C when its average is 12C.

The bureau’s long-range forecast for winter has warned of an increased likelihood of warmer than average maximum and minimum temperatures across most of the continent, as well as drier than usual conditions for much of the south-east.

Last week the bureau said there were developing signs that an El Niño weather system could be developing over the tropical Pacific Ocean, which pushes Australia’s east and south towards drier and hotter conditions in winter and spring.