A rapid weakening of Pacific trade winds may hasten the decline of this year’s La Nina weather system, the Bureau of Meteorology says.

Four of eight models surveyed by the bureau suggest La Nina is likely to last until late summer, while a few continue the event into autumn.

Large parts of eastern Australia have been drier than average for the past two or three months, the opposite of what is typically expected during La Nina, due to the current system’s weakness.

“Climate patterns have been significantly different from those observed in the last strong La Nina of 2010-12,” the bureau says.

Typically La Nina brings rain and a greater chance of flooding to Australia’s east, while the opposite El Nino system is associated with drought and bushfire risk.