The pattern of seasonal temperature odds across Australia is mostly a result of
continued warmth in the central to southeastern Indian Ocean, especially off
the west coast of WA.
Averaged over September to November, the chances are mainly between 60 and 75% for
above average maximum temperatures in northern Queensland, the northern two-thirds
of the NT and the far north of WA (see map). In some areas near the Gulf of
Carpentaria, the probabilities approach 80%. There are also 60-65% chances for a
warmer than normal spring in southwest WA, southeast SA, and western and central
So for every ten years with ocean patterns like the current, about six to eight
springs are expected to be warmer than average across the north of the country
as well as in parts of southwest and southeast Australia, while about two to four
are expected to be cooler. Across the rest of the country, the chances of a
warmer than average spring are between 50 and 60%, indicating roughly equal chances
for warmer or cooler than normal conditions.
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 large parts of the country,
with the exception of the southeast and far west where it is only weakly consistent
(see background information). Users therefore need to be cautious in applying this outlook in
southwest and southeastern Australia.
Average spring minimum temperatures are also favoured to be warmer than normal
across most of the country, with the exception of Queensland's southern half and
the northeast half of NSW (see map). The chances of increased overnight warmth
(averaged over the coming three months) are between 60 and 80% over most of Australia.
Or to put it another way, for every ten years with ocean patterns like the current, about six to eight
would be expected to warmer than average in terms of overnight temperatures
averaged over spring.
History shows the oceans' effect on minimum temperatures during spring to be
moderately to highly consistent over most of the country, except in parts of
southeast and eastern Australia where the effect is generally only weakly consistent.