For the July to September period, the chances of above average seasonal maximum
temperatures are between 60 and 70% over Australia's sub-tropics and southern tropical
regions, together with most of WA (see map).
So in years with ocean patterns like the current, about six or seven September quarters out
of every ten are expected to be warmer than average across these parts of the country,
with about three or four out of ten being cooler.
The chances of a warmer than average season are in the 50 to 60% range in southeastern
Australia, including Tasmania, and in the far north of the country.
The outlook pattern for maximum temperatures is due to roughly equal contributions
from higher than average temperatures in both the Indian and Pacific Oceans.
Outlook confidence is related to the consistency of the
influence of Pacific and Indian Ocean temperatures on seasonal
temperatures. During July to September, history shows this influence on maximum temperatures
to be moderately consistent in WA, the NT, Queensland, northern and eastern NSW, and
far northern Tasmania. Elsewhere it is only weakly consistent (see background information).
There is a moderate shift in the odds towards above average September quarter
minimum temperatures across the southern half of WA, and this is almost entirely due
to the recent increased Indian Ocean temperatures. The probabilities reach 60 to 70%
in this area, but in remaining parts of the country, the chances of above normal overnight temperatures
averaged over July to September are between 50 and 60%.
History shows the oceans' influence on minimum temperatures during July to
September to be moderately consistent over Queensland and the east of the NT, the
southern half of WA, and parts of north and east NSW. Elsewhere the
influence is only weakly or very weakly consistent.