Curious about what the weather has in store for summer?
October kicks off Australia’s peak time for severe weather – with increased risk of everything from heatwaves and bushfires to thunderstorms, floods and cyclones – continuing for months.
This year, the weather bureau says extreme heat is practically a given. But competing climate drivers make other questions harder to answer – will it be wet or dry? And what sort of fire season can we expect?
Here’s what we know – and what we still don’t know – about what lies ahead.
Daytime, night-time temperatures – how hot will they get?
Abnormally hot days and warmer-than-average nights are likely, with the weather bureau expecting periods of extreme heat across much of the country.
The prospect of unusually high daytime temperatures is highest for Tasmania, says Bureau of Meteorology senior climatologist Felicity Gamble, who says the state has a 60-70% chance of exceeding the norm.
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“This is the warmest time of year. And given the outlook, we do anticipate there being a reasonable number of heatwaves this year,” she says.
The only place likely to buck the trend is the New South Wales coastline, with extra moisture after a very wet winter moderating the daytime heat.
Overnight temperatures will be unusually warm across the board, Gamble says, which suggests they will be in the top 20% on record.
Will record sea surface temperatures continue?
September sea surface temperatures around Australia were the warmest on record, Gamble says, continuing the pattern of warmest or second-warmest seas each month since July 2024.
“That ocean heat is certainly persisting,” she says. “In the Australian region specifically, we are expecting those warmer than average temperatures to continue through at least until the end of summer, potentially even warming further.”
Prof Moninya Roughan, an oceanographer at the University of NSW, says some of the fastest warming is occurring in waters off southern NSW.
That’s because the East Australian Current, which flows down the coast carrying water from warmer to cooler regions, was pushing further down south and spending more time in southern NSW, she says. There were also more eddies, trapping warmer water for longer.
“Summer is coming sooner and it’s lasting longer. So the warm waters arrive earlier in the season, and they stay longer than they used to,” Roughan says, with climate change playing a significant role.
Wetter or drier? It could go either way
When it comes to rain, Gamble says there’s a range of possibilities from November on with “no particular tendency towards wet or dry”.
“The chances of above or below average rainfall are roughly equal across much of the country,” she says.
Climate drivers linked to wetter conditions – warmer oceans, the chance of a weak La Niña in spring and a negative Indian Ocean dipole – are battling the drying effects of sudden stratospheric warming and a range of secondary climate patterns.
“There’s a bit of a tug-of-war going on,” she says, “that’s why we are seeing a relatively weak signal in the rainfall forecast.”
One exception, however, is far north Queensland, which has a strong chance of a wetter than average summer.
Storms and cyclone season kicks off
“October to December is when much of the east coast of Australia has the highest risk of severe thunderstorms,” says Gamble, particularly for large parts of NSW and southern Queensland.
Severe storms can bring bursts of destructive winds, intense rain, lightning, hail and the potential for tornadoes, she says. While further south, storms combined with increased pollen can bring the risk of thunderstorm asthma.
Further north, Australia’s tropical cyclone season runs from 1 November to 30 April. Most years see at least one, and usually three or four cyclones making landfall.
Fire outlook still to come
December to February is peak fire season and the summer bushfire outlook is not due until November.
Gamble says there is usually high fire activity regardless, with the level of risk depending on factors such as the amount of fuel to burn, management and weather conditions at the time.
“Southern Australia is one of the most fire-prone regions in the world and there’s always a risk of bushfire,” she says.
