The pattern of seasonal rainfall odds across southeastern Australia is a result of
continuing higher than average temperatures over parts of the south tropical
Pacific Ocean, and also in parts of the tropical Indian Ocean.
A higher contribution has come from the Indian Ocean.
Averaged over spring, the chances are between 60 and 65% for above-normal
maximum temperatures over much of Victoria and adjacent areas of eastern and
southeastern SA (see map).
So in years with ocean patterns like the current, about six September to
November periods out of every ten are expected to be warmer than average over
these parts of southeast Australia, with about four out of ten being cooler.
In remaining areas, the chances of exceeding the average spring maximum
temperature are between 50 and 60%.
Outlook confidence is related to how consistently the Pacific and Indian
Oceans affect Australian temperatures. During spring, history shows this effect on
maximum temperatures to be moderately consistent across most of SA and NSW
(see background information). The effect is only weakly consistent in Victoria, Tasmania,
southeastern SA and the southern border areas of NSW, so users should be
cautious in applying this outlook in Victoria and SA.
Average spring minimum temperatures are favoured to be warmer than normal across
virtually all of southeastern Australia (see map). The chances of increased overnight
warmth (averaged over the coming three months) are mainly between 60 and 75%.
History shows the oceans' effect on minimum temperatures during spring to be moderately
consistent over SA and most of western NSW. Elsewhere the effect is generally only