The city's rain gauges gathered 12.6 millimetres as of the monthly cut-off of 9am on Monday, the least for a July since 1995, according to Bureau of Meteorology data for Observatory Hill.

A rain band had brought about 6 millimetres of rain by late afternoon, Sydney's first rain in 16 days, which will be put on the bureau's August ledger.

The arrival of another low pressure system on Thursday should bring the next chance of reasonable falls, Tom Hough, a meteorologist with Weatherzone, said. The bureau is forecasting 8-15 millimetres for the day.

Sydney smashed its record July maximum temperature on Sunday with the mercury climbing to 26.5 degrees, a full 0.6 degrees above the previous high for the month set in 1990.

Brewarrina's 30.2 degrees on Sunday in the state's north-west was the hottest for July at that site, and the first July reading above 30 degrees in NSW since 1958, the bureau said.

Monday's top temperature of 16.5 degrees was the coolest in almost three weeks. Even so, July's average maximum reading of about 19.1 degrees will be close to 3 degrees above the long-run average for the month, and trailing only July 2013's record 19.45 degrees, Mr Hough said.

Dry, mild outlook

The near-term outlook is for a couple more fronts crossing southern Australia by the end of the weekend but neither of them will make much difference to Sydney's ongoing mild conditions, he said.

According to the Bureau of Meteorology's three-month outlook, most of southern Australia can expect relatively dry conditions to persist, particularly for August.

(See bureau chart below showing the odds of below-average rain for August.)

The dry winter and outlook have already prompted fire authorities to warn of the possibility of an early and active fire season across southern Australia.

Meteorologists note the main driver for this winter's poor rainfall has been the more southerly location than usual of the high-pressure ridge over Australia. That has meant rain-bearing fronts have tended to be pushed further south than typical for winter, largely missing the continent.

The lack of cloud cover has also resulted in cold nights for many regions but also well-above average temperatures during the day.

On Saturday, Victoria matched its record July maximum temperature, with 27.1 degrees recorded at Mildura on the Murray. That equalled the temperature reached at Robinvale in July 1975.

The bureau's outlook for August-October points to continuing warmer-than-usual conditions, particularly for next month.

(See chart below showing the odds favour above-average temperatures for almost all of Australia.)

For Sydney, the coming week is likely to bring a narrow range of temperatures. Overnight lows will range between 8 and 10 degrees on most mornings with daytime readings between 18 and 20 degrees, the bureau said.

Alpine regions, which have had a slow start to the season compared with a year ago, may collect a fresh layer of snow on Thursday with some sites collecting up to 10 centimetres, Mr Hough said.

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