The pattern of seasonal temperature odds across Australia is a result
of recent warm conditions in the Indian Ocean and a warming Pacific.
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
country and parts of Tasmania. In many areas the chance is above 70%, with
values above 80% in western WA, southern Queensland and northern NSW.
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 Australia, 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 country, with the exception of the southeast and far north where
it is only weakly consistent (see background information).
The outlook for mean minimum temperatures over August-October is broadly similar,
with moderate to strong shifts in the odds favouring warmer than normal
conditions in most areas. Apart from Tasmania and some areas of northern
Australia, the chance of a seasonal average above the long-term median minimum temperature
is between 60 and 80%, with values above 80% in western WA. In contrast,
35 to 40% chances across Cape York in Queensland indicate a below average
seasonal minimum is favoured.
History shows the oceans' effect on minimum temperatures in August to October to be
moderately consistent over the southern half of WA, much of Queensland,
NSW and SA. Elsewhere the effect is generally only weakly consistent, so this
outlook should be used with caution in those areas.