Climate outlook for August to October

Issued 27 July 2017

Climate outlook overview

  • August to October rainfall is likely to be below average for most of southern mainland Australia.
  • August rainfall is very likely to be below average for the southern half of mainland Australia, while Tasmania is likely to be wetter than average.
  • Daytime and night-time temperatures are likely to be warmer than average for most of Australia. Chances are highest in northern and southeastern Australia, where there is a greater than 80% chance of warmer than average days and nights.
  • August is very likely to see warmer days nationwide, with most of the country having a greater than 80% chance of higher than average maximum temperatures.
  • Both of Australia's major climate drivers at this time of year, the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), remain neutral. This means more localised influences such as moderate shifts in the location and strength of the subtropical ridge, local sea surface temperatures and even soil moisture levels are likely to be affecting this outlook.

Drier August to October likely for southern mainland

  • August to October rainfall is likely to be below average for most of southern mainland Australia. Elsewhere, there is no strong signal towards a wetter or drier than average three months.
  • August rainfall is likely to be below average for the southern half of mainland Australia, with the highest chances over southern NSW. Conversely, Tasmania is likely to be wetter than average.
  • For this outlook, decreased westerly flow is forecast for southern to southeastern Australia, which tends to mean fewer rain systems likely for areas inland of the Great Dividing Range.
  • Historical outlook accuracy for August to October is moderate for most of Australia, but low in parts of central Queensland and interior WA. See map for more detail.

Warmer days and nights for most of Australia

  • Daytime and overnight temperatures are likely to be warmer than average for most of Australia. For northern and southeastern Australia there is a greater than 80% chance of warmer than average days and nights.
  • August in particular has a very high likelihood of warmer days nationwide, with most of the country having a greater than 80% chance of warmer than average days.
  • Historical accuracy for maximum temperatures is moderate over the southern half of mainland Australia, Queensland, and the Top End of the NT. Elsewhere, accuracy is low. Minimum temperature accuracy is moderate for northern Australia, parts of SA, northern NSW, and Tasmania, but low elsewhere.

Climate influences

  • Both of Australia's major climate drivers at this time of year, the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), remain neutral. This means more localised influences such as moderate shifts in the location and strength of the subtropical ridge, local sea surface temperatures and even soil moisture levels are likely to be affecting this outlook.
  • For this outlook, decreased westerly flow is forecast over southern to southeastern Australia, which tends to mean fewer rain systems likely for areas inland of the Great Dividing Range. This can be seen in the outlook map for August to October, where the drier than average pattern begins inland over southeast Australia.
  • In addition to the natural drivers such as the El Niño–Southern Oscillation 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.