Climate outlook for October 2020 to January 2021
Published Date: 24 Sep 2020
The Bureau of Meteorology has released the climate forecast from October 2020 to January 2021.
Climate outlook overview
- The remainder of the year is likely to see above average rainfall across the eastern two thirds of the country.
- October to December days are likely to be warmer than average across far northern Australia, and the far south-east, but cooler than average in southern WA through SA to NSW and the southern half of Queensland.
- Nights during October to December are very likely to be warmer than average across much of Australia, except areas of south-western WA.
- The Bureau's ENSO Outlook is at La Niña ALERT, meaning there is around a 70% chance of La Niña forming in 2020.
- Models suggest the Indian Ocean Dipole (IOD) index could meet negative threshold values during October.
- La Niña and a negative IOD typically increase the likelihood of above average rainfall across much of Australia during spring and early summer.
Wet end to 2020 for much of Australia; particularly during October
- October to December is likely to be wetter than average for much of mainland Australia and northern and eastern Tasmania (greater than 75% chance in much of this area). Chances of a wetter or drier than average three months are roughly equal for much of north-west WA and the Kimberley.
- October is very likely (greater than 80%) to have above average rainfall across much of the eastern two thirds of mainland, and is also likely (65 to 75% chance) to be wetter than average for south-coast and eastern WA and north-east Tasmania. Most remaining parts of WA have roughly equal chances of a wetter or drier than average October.
- In the shorter term, the fortnight 28 September to 11 October is likely to be wetter than average for large parts of northern, central, and eastern mainland Australia. Parts of north-west WA extending from the Pilbara coast into the state's center are likely to be drier than average.
Warmer days in the northern coasts and far south-east for the remainder of 2020; warmer nights except in south-west WA
- Daytime temperatures for the fortnight 28 September to 11 October are likely to be above average for northern and western Australia, Tasmania, and Victoria. Days are likely to be cooler than average in greater south-east Queensland. Nights during this period are likely or very likely to be warmer than average nearly everywhere.
- For October, days are likely to be warmer than average for the far north, Tasmania, and much of Victoria; but cooler than average for large parts of southern WA, SA, NSW, north-west Victoria, and the southern half of Queensland. Nights are very likely to be warmer than average for most of Australia, but chances of above or below average minima are roughly equal in parts of south-west WA and the eastern Pilbara.
- Days are likely to be warmer than average during October to December across the coasts of far northern Australia, extending into northern WA, and in the far south-east of the country. Cooler days are likely (60 to 75% chance) for much of southern WA, parts of SA, much of NSW, and central to south-eastern Queensland.
- Night-time temperatures for October to December are very likely to be warmer than average for most of Australia (greater than 80% chance in most areas), although there are equal chances of above or below average temperatures for south-west WA.
Maximum temperature maps
Minimum temperature maps
- The Bureau's ENSO Outlook is at La Niña ALERT, meaning the chance of La Niña developing in the coming months is around 70%. This is roughly triple the normal risk.
- The Bureau's model indicates that La Niña conditions are likely to persist in the tropical Pacific Ocean until at least early 2021.
- All eight surveyed international climate models anticipate La Niña thresholds will be met during October, with five maintaining La Niña values into early 2021.
- The Indian Ocean Dipole (IOD) index is currently neutral.
- Most models suggest the IOD index will meet negative IOD values during October, with several maintaining these values into November.
- The Southern Annular Mode (SAM) is currently positive, and is expected to dip briefly into negative values before becoming weakly positive in the first half of October. Positive SAM during spring is typically associated with wetter and cooler than average conditions in parts of eastern Australia.
- Australia's temperature and rainfall variability are also influenced by global warming caused by human activities. Australia's climate has warmed by around 1.4 °C since 1910, while southern Australia has seen a reduction of 10–20% in cool season (April–October) rainfall in recent decades.
- The Bureau's climate model uses the physics of our atmosphere, oceans, ice, and land surface combined with millions of observations from satellites and on land and sea. As a result, it incorporates the influence of climate change and natural climate drivers like ENSO, IOD, the MJO and SAM in its outlooks.