Grain farmers could lose up to 40 per cent of their profits if La Niña weather events lead to a wet harvest season, the Victorian Farmers Federation (VFF) warns.
Four of seven climate models surveyed by the Bureau of Meteorology suggest La Niña could return by early-to-mid spring, potentially leading to the third consecutive La Niña summer.
VFF Grains President and Rutherglen farmer Ashley Fraser said the season has been going well for grain growers, and more rain over the next month or two would make it even better.
But heavy rain past mid-October could change things dramatically.
"Crops are looking really good at the moment, and as the days lengthen off from here on in and the temperatures slowly increase, we'll be set up for a good yield," he said.
"But if it's wet at harvest, that's the thing the farmers are really going to be worried about, and that's what's going to hurt them."
Mr Fraser said harvesting wet could cause high-quality grain to be downgraded.
"It could wipe 25 to 30, even up to 40 per cent off their price that could be achievable," he said.
"The yield might still be there, but if the grain quality is downgraded the farmers will take a real hit on that front."
He said it could also lead to other problems, like green growth coming up through the crop and wheat being "shot" or "sprung", which means the seeds have started to sprout before they've been harvested.
"Unfortunately there's not a lot that can be done preparation-wise for that," Mr Fraser said.
"You could make sure you've got access to a drying facility, other than that you've really got to wait and see."
A matter of luck
The Bureau of Meteorology stressed that the prediction did not guarantee a La Niña summer.
Climate models and indicators have shifted, meaning they now met the La Niña "alert" criteria.
"And in the past, when we have met the La Niña alert criteria, La Niña itself has gone on to form around 70 per cent of the time," senior meteorologist Jonathan How said.
But Mr How said it was likely there would be a fair amount of rain over the time when harvest would start.
"The three-month climate outlook shows a high chance of above average rainfall for most of the eastern two-thirds of the Australian mainland between September and November."
Mr Fraser said it's just another thing to keep in mind during a tumultuous time for farmers.
"We have had a couple of decent years in a row, however the price of fuel and chemical and fertiliser have all increased our cost of production dramatically."
The war in Ukraine and grain shortages in Europe have pushed up the prices for Australian canola and barley, which somewhat offset production costs.
But when it came to the possibility of a wet harvest, he said it would just be a matter of when and where large storms hit.
"Last year I know we could see rain going through to the north of us. Those farmers under that got 60-70 millimetres, and 30 kilometres to the south you got nothing," Mr Fraser said.
"And that could be the other way around this year, it's just luck of the pluck."