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 above 60% for above-normal
maximum temperatures in the northern parts of southeastern Australia, with 65 to
70% chances in southern Queensland (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 SE Australia, with about three or four out of ten being cooler.
Over Victoria, and the remaining parts of NSW and SA, the chances for a warmer than
average season are between 55 and 60%, while in Tasmania mainly they're between 50
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 southern Queensland,
northern and eastern NSW, northern SA and far northern Tasmania. Elsewhere in
southeastern Australia it is only weakly consistent (see background information).
Average seasonal minimum temperatures are favoured to be warmer than normal across
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 this region, while in remaining parts of the southeast 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 southern Queensland, parts of north and east NSW,
and along the Eyre Peninsula in SA. Elsewhere in southeastern Australia the
effect is only weakly or very weakly consistent.