Climate outlook for May to July

Issued 28 April 2016

Climate outlook overview

  • May to July rainfall outlook: above average for large parts of mainland Australia.
  • Daytime temperature outlook: warmer than average for the tropical north and parts of southern Australia.
  • Overnight temperature outlook: warmer than average across the nation.
  • Climate influences include a very warm Indian Ocean, a rapidly weakening El Niño and warm sea surface temperatures surrounding much of Australia (see the Climate Influences section).

Increased chance of wet conditions across large parts of mainland Australia

  • May to July rainfall is more likely to be above average across most of mainland Australia. Southwest WA, southeast Australia and the tropical north have roughly equal chances of a wetter or drier three months.
  • Most of the country has roughly equal chances of a wetter or drier May.
  • The current outlook reflects a combination of a rapidly weakening El Niño, very warm Indian Ocean temperatures and warm sea surface temperatures around much of the Australian coast.
  • Historical outlook accuracy for May to July is moderate over most of eastern Australia and WA, but is lower in patches across the central south, and the tropical north. See map for more detail.

Warm nights expected to continue throughout Australia

  • May daytime and night-time temperatures are very likely to be warmer than average for most of Australia.
  • Warmer than average days are likely for the tropical north, and southern parts of Australia for the May to July period.
  • Nights are strongly favoured to be warmer than average across the country, with a greater than 80% (or eight in ten) chance of warmer nights for large parts of Australia for the May to July period.
  • The current outlook reflects a combination of very warm Indian Ocean temperatures, a rapidly weakening El Niño, and warm sea surface temperatures surrounding much of Australia.
  • Historical maximum temperature accuracy for May to July is moderate to high over most of Australia. Minimum temperature accuracy is moderate for most of Australia, except for parts of southeastern Australia, where accuracy is low to very low.

Climate influences

  • The 2015–16 El Niño is rapidly declining, with models forecasting a return to a neutral ENSO conditions within the next month. Further cooling of the tropical Pacific may lead to the development of La Niña by the end of June—the end of this outlook period.
  • Historically, after El Niño events end, warmer days tend to persist over northern and eastern Australia, with warmer nights present across much of Australia.
  • Sea surface temperatures are above average across much of the Indian Ocean, as well as for waters surrounding Australia. These waters near the Australian coastline have seen an increase in heat content due to the breakdown of El Niño in recent months. These warmer waters in the Indian Ocean may provide extra moisture for rain systems as they cross Australia.
  • There is also an increased chance of a negative Indian Ocean Dipole developing late in the outlook period. This typically brings above average rainfall to southern parts of Australia. However, this influence is likely to be limited by increased mean sea level pressure to the south of the continent. Hence the southwest and southeast parts of Australia have roughly equal chances of a wetter or drier three months.
  • It should be noted that northern Australia officially enters its dry season at the start of May. For the May to July period, large parts of northern Australia typically have a median rainfall that is less than 10 mm for the 3 months.
  • 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.