Climate outlook for December 2020 to March 2021
Published Date: 26 Nov 2020
The Bureau of Meteorology has released the climate forecast from December 2020 to March 2021.
Climate outlook overview
- December to February rainfall is likely to be above average across most of Australia, except west coast Tasmania.
- Average daytime temperatures during December to February are likely to be above the long-term average across parts of southeast and far west Australia, as well as along the northern coastline.
- Average night-time temperatures during December to February are very likely to be above the long-term average across almost all of Australia.
- La Niña is underway in the tropical Pacific. La Niña typically increases the likelihood of above average rainfall across eastern Australia during summer.
December to February wetter than average for nearly all of Australia
- December to February is likely to be wetter than average for nearly all of Australia (greater than 70% chance in most areas, greater than 80% chance along the Queensland coast), except Tasmania where equal chances of wetter or drier conditions are more likely. A similar outlook exists for December though the likelihood of above average rainfall is not as high (greater than 65% chance in most areas).
- The fortnight 30 November to 13 December is likely to be wetter than average for most of the northern WA (greater than 70% chance), as well as most of western SA, northern NT and Queensland (greater than 60% chance). Drier than average conditions are more likely along the far southwest coast of WA (greater than 60% chance).
- While the outlooks indicate wetter than average conditions, southern parts of Australia are entering into their drier season, so rainfall is not likely to be sufficient to relieve long-term rainfall deficits.
Warmer days for much of the southeast, as well as the far north and far west during December to February; warmer nights very likely for all of Australia
- Averaged over the fortnight 30 November to 13 December, maximum for most of the eastern half of mainland Australia as well as western WA (greater than 75% chance). Cooler daytime temperatures are more likely over the Kimberly and along the Eucla coast. On average, minimum temperatures during this period are very likely to be warmer than the long-term mean across almost all of Australia (greater than 80% in most areas), except over southern Australia where roughly equal chances of warmer or cooler minimum temperatures are more likely.
- The average maximum temperature for December to February is likely to be higher than the long-term average for Victoria and adjacent parts of SA, Tasmania, the far west of WA, the northern coastlines of the NT and Queensland, and around the NSW/Queensland border. It is likely to be cooler than the long-term average for south coast WA and northeast WA.
- The average minimum temperature is very likely (greater than 80% chance) to be higher than the long-term average across Australia during December to February, apart from around southeast WA where there is a closer to 60% chance.
Maximum temperature maps
Minimum temperature maps
- The Bureau's ENSO Outlook is at La Niña: La Niña remains active in the tropical Pacific Ocean.
- Model outlooks suggest the La Niña will peak around December or January and is likely to persist until at least the end of February 2021.
- Warmer sea surface temperatures to the north of Australia are likely to persist and contribute to the wetter outlook.
- The Southern Annular Mode (SAM) is neutral but is forecast to return to more positive values over the next week. La Niña and a strong polar vortex favour a positive SAM, with generally positive values expected over the 2020–21 summer. This typically enhances the wet signal of La Niña in parts of eastern Australia, although western Tasmania is often drier.
- The Indian Ocean Dipole (IOD) is neutral. Most models indicate that the IOD will remain neutral over the coming months so is not likely to have any impact on Australian rainfall.
- Australia's temperature and rainfall variability are also influenced by global warming caused by human activities. Australia's climate has warmed by 1.44 ± 0.24 °C since 1910 while recent decades have seen increased rainfall during the northern wet season (October–April) , with more high intensity and short duration rainfall events.
- 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.