El Niño is a natural climate event that generally brings warmer and drier conditions over Australia and the whole globe on average.
CSIRO researchers say El Niño is one factor associated with drought, but they stress it is not the only one.
Droughts typically develop after more than a year of below-average rainfall, compounded by rising temperatures, evaporation, low soil moisture and depleted water storage.
For the Murray-Darling Basin, El Niño significantly increases the odds of a dry spring, a concern for irrigators and dryland farmers heading into the second half of the year.
CSIRO Group Leader Rose Roche said the timing of lower rainfall translating to crop and pasture impacts would depend heavily on starting soil moisture levels.
"We notice drought impacts more when relatively low rainfall years translate to poor crop and pasture growth, or prolonged dry years see water storage dams run low or empty," Dr Roche said.
She also drew a distinction between meteorological drought, when rainfall falls short, and agricultural drought, when farmers face genuine economic hardship.
Stored soil moisture and strong commodity prices can carry producers through lean rainfall periods, while poor prices can create hardship even in reasonable seasons.
CSIRO Senior Research Scientist Carly Tozer cautioned against treating El Niño as a uniform threat across the country, noting its influence varied significantly by region.
"El Niño is a good indicator of dry conditions in eastern Australia as a whole, but we are such a vast country the impact is varied between regions," Dr Tozer said.
Other climate drivers, including the Indian Ocean Dipole and the Southern Annular Mode, also shape Australia's rainfall variability and must be considered alongside El Niño forecasts.
