The pattern of seasonal temperature odds across Western Australia is a result
of recent warm conditions in the Pacific Ocean.
The chance that the average November-January maximum temperature will exceed the
long-term median maximum temperature is between 40 to 45% across the Interior and adjacent
areas, decreasing to 35% in parts of the northeast Interior. This means that for
every ten years with ocean patterns like the current, about three to four would
be expected to be warmer than average for this region, or in other words, six to
seven would be expected to be cooler than average, during the November-January
period. The chance of exceeding the median maximum temperature for much of the
remainder of WA is between 40 and 60%, meaning that a warmer than normal season is
about as equally likely as a cooler than normal one.
Outlook confidence is related to how consistently the Pacific and Indian
Oceans affect Australian temperatures. During November to January,
history shows this
effect on maximum temperatures to be moderately consistent over much of
the west and south WA, and in the far north Kimberley.
(see background information).
The average minimum temperature for November to January is favoured to be
above the long-term median minimum temperature across all of WA (see map). The chances of
increased overnight warmth (averaged over the coming three months) are generally
between 60 and 70%, and rise to 75% in parts of southern WA.
History shows the oceans' effect on minimum temperatures during November to January to be moderately
consistent over much of WA, whilst it is only weakly consistent across much of the Kimberley
and adjacent northern Interior.