The pattern of seasonal temperature odds across Australia is a result of recent
higher than average temperatures (although with a cooling trend) in the tropical
Pacific Ocean, and also in parts of the tropical and sub-tropical Indian Ocean.
Each Ocean's influence is similar.
Averaged over July to September, the chances are mainly between 60 and 70% for above-normal
maximum temperatures in Queensland, the NT, WA, northern SA and northern NSW (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 in these
parts of Australia, with about three or four out of ten being cooler.
In the southeast and the rest of SA, the chances for a warmer than
average season are between 55 and 60%.
Outlook confidence is related to how consistently the Pacific and Indian
Oceans affect Australian temperatures. During July to September, history shows this
effect 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).
Average seasonal minimum temperatures are favoured to be warmer than normal across
southern WA, southern Queensland and northern New South Wales (see map). The chances of
increased overnight warmth (averaged over the coming three months) are between 60
and 65% in the Queensland/NSW region, and between 60 and 80% in WA.
In remaining areas the probabilities are in the neutral 50 to 60% range.
History shows the oceans' effect on minimum temperatures in 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
effect is only weakly or very weakly consistent.