Climate outlook for September to November

Climate outlook overview

• The spring (September to November) climate outlook, issued 15 August 2019, indicates a drier than average season is likely for most of mainland Australia.
• Spring maximum temperatures are likely to be warmer than average, except in the southeast, which has a 50-50 chance of warmer or cooler than average days.
• Spring nights are likely to be warmer across northern and western Australia. With more cloud-free days and nights expected, there remains an increased risk of spring frost in susceptible areas.
• Climate influences include a positive Indian Ocean Dipole (IOD) and an ENSO-neutral tropical Pacific Ocean. 

Service change: starting 29 August 2019, the Bureau's Climate Outlooks will be released from 3:00pm AEST. The change in release time allows us to implement a range of operational updates aimed to improve our service.

Drier spring likely

• A drier than average spring is likely for most of Australia, except the western coastline and far southeast.
• The likelihood of drier conditions is stronger in October compared with September. September is likely to be drier across the north and small scattered areas of the south, while October is likely to be drier across most of the mainland.
• Historical outlook accuracy for spring is moderate to high for most of the country, but low along the NT-WA border, and the west coast of WA. See map for details.

Warmer spring likely for most of Australia, except the southeast

• Spring days are likely to be warmer than average for most of Australia, except in southeast SA, Victoria and Tasmania.
• Nights are also likely to be warmer than average for western and northern Australia. Much of southeast Australia, extending into southern SA have near-equal chances or warmer or cooler spring nights overall. 
• October nights are likely to be cooler than average in parts of southern Australia. The forecast drier than average conditions and associated cloud-free nights, in conjunction with dry soils, is likely to increase the risk of late-season frost in suseptible areas. 
• Historical accuracy for spring maximum temperatures is moderate to high for most of Australia, except parts of northern SA. Minimum temperature accuracy is patchy, but generally moderate across much of eastern Australia including Tasmania, and the tropical north. Moderate to low accuracy is seen across western WA and SA, with low accuracy in central WA, the central NT and parts of western Queensland. See map for more details.

Climate influences

• The Indian Ocean continues to exhibit patterns consistent with a positive Indian Ocean Dipole (IOD). Positive IOD conditions are forecast to continue for spring. Typically this means below average rainfall for much of central and southern Australia during winter-spring, which is consistent with the current spring outlook. The positive IOD is likely to be the dominant climate driver for Australia during the next three months. 
• Tasman Sea pressure patterns are favouring a reduction in onshore flow for parts of the east coast of Australia, and likely contributing to the warmer and drier conditions forecast across NSW and southern Queensland. 
• The El Niño–Southern Oscillation (ENSO) is expected to remain neutral for the remainder of 2019. 
• 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.