The La Nina phenomenon is heading back to Australia this summer - but that does not necessarily mean we should be braced for cooler temperatures and more rain.

The Bureau of Meteorology says the risk of a "La Nina event" over the next few months is about 70 percent, about three times the normal figure.

Manager of Climate Prediction Services Andrew Watkins said Australia was looking set for an unusual La Nina event.

"Normally you would expect to see more widespread rainfall, more cloud cover and cooler temperatures over much of particularly eastern Australia," he said.

"But this time we've got some opposing climate drivers, and those are going to keep things a little more benign, a little warmer than normal, and not really a strong swing in our rainfall."

The bad news is the La Nina will not reduce the risk of bushfires over summer, as it normally would.

"We're not really looking at widespread cool or wet conditions," Dr Watkins said.

"In other words, with a shift to La Nina alert, normally the bushfire risk would go down, but unfortunately this time the bushfire risk remains the same."

However, there is no forecast of the same kind of widespread flooding that the country felt in the last La Nina cycle, from 2010 to 2012.

During that time, Cyclone Yasi struck the far North Queensland coast, and there was heavy flooding in Queensland, much of NSW, northern Victoria and central Australia.

Only the south of Western Australia had lower than average rainfall during that La Nina cycle.

La Nina is Spanish for "the little girl" while El Nino means "the little boy".