"There is no strong signal from our models of getting widespread, soaking rains in the next few months," Mr Dutschke said.

Most of Australia has been dry lately, with some days - such as Tuesday - being almost completely rain-free across the entire continent.

Across south-eastern Australia, drought is starting to bite, with much of NSW enduring serious or severe water deficiencies in the past six months. Rainfall for January-June was half the average, and the state's driest start to a year since 1986, the bureau said.

Over the past 15 months, the rainfall deficiencies are severe and even worst on record for eastern NSW, including severe conditions around Sydney, the bureau noted last week.

The odds also strongly favour above-average day-time temperatures over the August-October period as farmers start to look towards the spring.

For Sydney, the near-term outlook is for low overnight temperatures. Inland parts of Sydney could dip below freezing over the weekend - such as minus 3 degrees on Sunday in Richmond - with 5-6 degrees tipped for eastern suburbs from Friday to Monday.

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The current drivers of the big dry include a cooling off of the Indian Ocean near Australia, that has removed a source of moisture that can find its way across the country, Mr Dutschke said.

Conditions are also tilting towards an El Nino event in the Pacific late year.

During El Ninos, easterly equatorial winds slow or reverse, typically reducing rainfall for eastern Australia - an outcome many farmers will be hoping does not eventuate.

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