Climate outlook for autumn (March to May)

Issued 23 February 2017

Climate outlook overview

Autumn (March to May) rainfall is likely to be below average over the southern two-thirds of Australia.
March is likely to be hotter and drier than average across most of Australia, except the far north and west.
Warmer autumn days and nights are likely across most of Australia, except northwest Australia where days and nights are likely to be cooler than average.
The drier than average outlooks are likely a result of forecast higher than normal pressure across western and southern Australia, meaning fewer rain-bearing systems are likely to cross the coast (see the Climate Influences section for more detail).

March is likely to be drier than average across most of Australia. Western WA, the Top End of the NT, Cape York Peninsula in Queensland and parts of the NSW coast have roughly equal chances of a wetter or drier month.
Autumn (March to May) rainfall is likely to be below average for the southern two-thirds of Australia. Elsewhere, the chances of a wetter or drier season are roughly equal.
The drier than average outlooks are likely a result of forecast higher than normal pressure over western and southern Australia, meaning fewer rain-bearing systems are likely to cross the coast.
Historical outlook accuracy for March to May is moderate to high over eastern and northern Australia as well as parts of western WA, with mostly low accuracy elsewhere.

Daytime temperatures are very likely to be warmer than average in March for most of southern and eastern Australia.
Autumn (March to May) maximum temperatures are likely to be warmer than average across most of Australia, except the northern NT, where daytime temperatures are likely to be cooler than average. Most of the country has high chances of warmer days, with the likelihood exceeding 75% across most of southern and eastern Australia.
Similarly, autumn minimum temperatures are likely to be warmer than average across most of Australia, but cooler than average in northern WA, and the northern NT.
Maximum temperature accuracy is moderate to high over most of Australia, except the southern mainland, where accuracy is low to very low. Minimum temperature accuracy is moderate to high over the northern half of Australia and Tasmania, and low to very low over the southern half of the mainland.

The El Niño–Southern Oscillation (ENSO) remains neutral, but the tropical Pacific Ocean is steadily warming.
The Indian Ocean Dipole (IOD) has little influence on Australia from December to April.
Without a strong influence from the Indian or Pacific oceans, secondary climate drivers contribute more to the outlooks. Higher than average pressure is forecast over the Great Australian Bight and southern and western Australia, meaning fewer rain-bearing systems are likely to cross the coast.
The past two decades have seen autumn rainfall declines across much of the south. For example, 22 of the past 26 years have brought below-average rainfall to southeast Australia.
In addition to the natural drivers such as ENSO and the IOD, Australian climate patterns are being influenced by the long-term increasing trend in global air and ocean temperatures.
Bureau climatologists continually monitor the climate for any significant developments, with information on El Niño/La Niña and IOD events available fortnightly via the ENSO Wrap-Up. For a summary of Pacific and Indian Ocean outlooks, please see the Climate Model Summary.