The neutral pattern of seasonal maximum temperature odds
comes from both the La Niña pattern (cooler than average
temperatures in the equatorial Pacific), and
higher than average temperatures in the central to southeastern Indian Ocean.
Averaged over February to April, the chances are between 40 to 50% for above-normal maximum
temperatures over WA (see map).
So for every ten years with ocean patterns like the current, about five
February to April periods are expected to be warmer than average over
WA, with about five being cooler.
Outlook confidence is related to how consistently the Pacific and Indian
Oceans affect Australian temperatures. During the February to April period, history
shows the effect on maximum temperatures to be moderately consistent over parts of
central and northern WA, but over most of the state, the effect is only weakly
or very weakly consistent (see background information).
Minimum temperatures for the February to April period are favoured to be warmer than normal across
much of west of a line from the North West Cape, inland to around Carnegie and
south to the east of Esperance on the southern coast (see map). The chances of increased
overnight warmth (averaged over the coming three months) are mainly between 60
and 75% in this area. Across the rest of the state, the chances of the
seasonal mean minimum being above the long-term average are typically between 40 and 60%,
except in an area in northeastern WA where there is only a 35 to 40% chance
of exceeding the median.
History shows the oceans' effect on minimum temperatures during the
February to April period to be moderately to highly consistent in northeast WA, and
generally moderately consistent over the rest of the State, particularly the