The pattern of seasonal temperature odds across Australia is a result
of recent warm conditions in the Indian Ocean and a warming Pacific, with
the Indian dominating the WA outlook.
The chance that the average August-October maximum temperature will exceed the
long-term median maximum temperature, is above 60% in all but the far north of the
Kimberley, increasing to above 80% in large parts of western and central WA.
This means that for every ten years with ocean patterns like the current, about six
to nine would be expected to be warmer than average during the August to October
period over most of WA, with about one to four years being cooler.
Outlook confidence is related to how consistently the Pacific and Indian
Oceans affect Australian temperatures. During August to October, history
shows this effect on maximum temperatures to be moderately consistent across
most of the state, with the exception of the Kimberley where
it is only weakly consistent (see background information).
The outlook for mean minimum temperatures over August-October is broadly similar,
with a moderate to strong bias in the odds favouring warmer than normal
conditions in most areas. With the exception of the far north of the Kimberley,
the chance of a seasonal average above the long-term median minimum temperature
is over 60% across WA, increasing to above 80% in large parts of western,
central and southern WA.
History shows the oceans' effect on minimum temperatures in August to October to be
moderately consistent over much of WA, particularly the southern half of the state.