Most of the nation shared the relatively hot and dry conditions. In NSW, for instance, it was the state’s fourth-hottest October – with daytime readings 3.3 degrees warmer than average – and its fifth driest with just a quarter of the usual rain.
So far in 2019, NSW is running at the hottest for any similar period for both mean and maximum temperatures, while having among the five driest January-October periods on record.
Sydney’s daytime temperatures were about 2.2 degrees warmer than usual last month. So far in 2019, the Harbour City is running at the warmest on record for both mean and maximum readings.
Rainfall was below average across the city last month, including less than half the usual total for Observatory Hill. So far this year that site, near Sydney’s CBD, has collected 824mm, or about four-fifths the norm.
Most other states have endured similar conditions. Victoria, for instance, posted its eighth-driest October on record. Mildura in the state’s north-west recorded no rain last month, only the second time this has happened in October in records that go back to 1946.
Melbourne was dry, too, last month, with below average rain across the city. Temperatures so far in 2019 are very much above average.
The bureau’s latest three-monthly outlook offers little relief for most of the country.
“November and December rainfall is likely to be below average across most of the country,” it said, adding that the relatively dry conditions were likely to extend through to the end of summer for most of eastern Australia.
For November to January, the odds are running at more than 80 per cent for warmer than average days for the Australian mainland.
“For summer, warmer than average days are likely nationwide,” the bureau said.
The extended dry and warm spell is partly the result of relatively cool waters off north-western Australia, reducing the convection that feeds north-western cloud bands that bring rain to the country’s south-east.
The so-called Indian Ocean Dipole has been at record positive levels in recent weeks, and may not break down to neutral conditions until next month, the bureau said.
Peter Hannam writes on environment issues for The Sydney Morning Herald and The Age.