Why Aussie weather forecasts have got it wrong during 'weird' summer

Even the experts have been left 'a bit surprised' by what's been going on with Australia's weather lately.

We were warned to expect a warmer, and drier than average, spring and summer, threatening to make life hot and sweaty for millions of Aussies. We were told to brace for heatwaves and bushfires. So what happened?

Although there has been heat and humidity, there's also been a whole heap of rain, and while spring forecasts were largely accurate, with both Sydney and Perth recording their hottest spring on record, some meteorologists have "been surprised" by the buckets of rain that have dumped down on the east in recent weeks.

Commuters being rained on in Sydney.
One Aussie meteorologist said he was surprised by how much rain had fallen on the country so far this year. Source: Getty.

Large parts of the country have been swamped by flooding just weeks into 2024, a situation in part due to ex-Tropical Cyclone Jasper. Many of those regions, mostly in Queensland and Victoria, are still being lashed by the effects of heavy rainfall, set to cost their local economies millions. Earlier this month in Victoria alone, some 200 millimetres fell on parts of the state in just days.

With the El Niño system arriving on our shores, after three years of wet conditions brought by La Niña, things haven't exactly been as expected, leaving some Aussies growing increasingly distrustful of the weather man.

'Weird' weather due to warmer ocean

While it's not abnormal to see heavy rainfall during an El Niño cycle, Dr Andrew King, climate scientist at Melbourne University, said the rainfall seen throughout the summer has caught him by surprise.

"I've been a bit surprised at how wet it's been — it's a weird El Niño, actually, because we've got very warm ocean conditions to the east of Australia, unusually warm," he said.

"And that's basically helping deliver more moisture and destabilising the atmosphere a bit, which is increasing the rainfall in the southeast of the continent. That wasn't really something that most people would have been expecting."

Aussies getting rained on in Melbourne.
Sometimes weather apps predict rain, and it ends up being sunny, and vice versa. Source: Getty.

Can we trust our weather apps?

If you're reliant on the weather app on your phone — regardless of whether you sport an iPhone or Android — this year you may have noticed a daunting little rain icon appear on certain days, only to later walk outside to sunny skies. You might also have seen a sunny icon, only to be dampened by rain.

With storms in general being tough to predict, even the experts sometimes get it wrong. But are we putting too much emphasis on our weather apps? Should we be taking these forecasts and "rain icons" with a grain of salt? Or, do we just not know how to interpret them?

A generic image of a weather app.
American companies like Apple using international data as well as local, which can produce varied results for Aussies. Source: Getty.

King says it's a little bit of both. Aussies should know what to expect from the apps, and know how to interpret them.

"Firstly, I think all the apps vary a bit," King told Yahoo News Australia. "The Bureau of Meteorology (BoM) for example will say there's a chance of showers and include a rain icon, when there's a relatively low likelihood, and it might just be at one point in the day — but the rest of the time, it's sunny," he said.

So when looking at your weather app, it really pays to look beyond the iconography and read the finer details.

Different apps use different models, meaning varied forecasts

According to King, most apps also use "different models", resulting in "slightly different forecasts". When it comes to Apple products for instance, the tech giant says it sources its weather data from a range of organisations, many of them based overseas. Though some of its data is from the BoM, it claims.

If tech companies behind weather apps are sourcing data from overseas, King said it might mean information is "less tailored to Australian weather climates". "The BoM is probably the best source of weather forecast information in Australia," he said, adding that for the most part the weather authority is as accurate as they can be at the time of forecasting.

"The American models are perfectly skilled. But the BoM uses its own model, which it runs at higher resolution, from Australia, so it can produce kind of finer scale information."

Apps using American models might "scrape data" a couple of times per day, but Australian resources "might update its forecasts more frequently".

"At least for a few hours, generally, yes [you can rely on the apps]," King said. "But it's better to use the BoM app, instead of say Google or Apple, if you're planning some kind of event that's outdoors several days in advance."

A BoM graph.
The hottest spring on record for was reported in Sydney and Perth last year. Source: BOM.

King also noted that often, if meteorologist gets a small detail wrong, it could "make quite a big difference". "On summers days, when the land really heats up, you can trigger local circulations, so things like sea breeze effects, because the sea is a lot slower to heat up, you get a breeze from the sea to the land," he said.

"The timing of those kinds of wind patterns is quite hard to forecast. And if you get it slightly wrong, that can make quite a big difference to a temperature forecast. So it can be hard to predict."

What's on the cards for the rest of summer?

The bulk of El Niño's effects are felt in spring, King said, meaning we're past the thick of it, and the cycle "will last probably another three or four months".

"At the moment, the BoM's outlook is for slightly wetter than normal conditions to persist in the southeast as we have these lingering high sea surface temperatures off the east coast, but also drier than normal conditions through the northern and western coasts," he explained.

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