Climate outlook for March to May (autumn)
Issued 25 February 2016
Climate outlook overview
- March to May favours above average rainfall in parts of southeast Australia but below average rainfall in the tropical north.
- March favours below average rainfall in both northern Australia and the southeast mainland.
- Daytime temperatures more likely to be warmer than average during autumn except in parts of the southern interior, while night-time temperatures are very likely to be warmer nation-wide.
- Climate influences include a very warm Indian Ocean, a weakening El Niño and warm sea surface temperatures surrounding much of Australia (see the Climate Influences section).
Increased chance of wet in southeast; dry in tropical north
- March is likely to be drier than average across northern Australia, and parts of southeast mainland Australia.
- For autumn (March to May), rainfall is more likely to be above average across the southeast, except eastern NSW and eastern Victoria. The tropical north is more likely to have a drier than average three months.
- The current outlook reflects a combination of a weakening El Niño, very warm Indian Ocean temperatures and warm sea surface temperatures near Australia.
- Historical outlook accuracy for March to May is moderate to high over eastern and northern Australia as well as parts of western WA, with mostly low accuracy elsewhere.
- In the northern tropics, March and April are the last months of the wet season. On average, April tends to receive much less rainfall than earlier wet season months. The current outlooks suggest the northern wet season is likely to end much drier than average.
Most of Australia very likely to have a warmer autumn
- Summer-like temperatures are likely to continue into March, with both daytime and night-time temperatures very likely to be warmer than average.
- For the three-month period (March to May), daytime temperatures are more likely to be above average across the country, except for northern and central SA, western NSW and western WA where the chances of a warmer or cooler season are roughly equal.
- Nights are favoured to be warmer than average nation-wide, except near Carnarvon, with a greater than 80% (or an eight in ten) chance of warmer nights for much of the country.
- The current outlook reflects a combination of very warm Indian Ocean temperatures, a weakening El Niño, and warm sea surface temperatures surrounding Australia.
- Maximum temperature accuracy is moderate to high over most of Australia, except over the southern mainland where accuracy is low to very low. Minimum temperature accuracy is moderate to high over the northern half of Australia and Tasmania, and low to very low over the southern half of the mainland.
Climate influences
- El Niño is steadily declining, with models forecasting a return to a neutral pattern in late autumn to early winter. During the latter breakdown part of the El Niño cycle, warmer days tend to persist over northern and eastern Australia, with warmer nights across much of Australia.
- In addition to El Niño, there are widespread warmer than average sea surface temperatures across much of the Indian Ocean, as well as waters surrounding Australia. The warmer waters are likely to reinforce local above average air temperatures.
- Soil moisture has been relatively low across northern and eastern parts of Australia, particularly in the drought-affected regions. This means there is less evaporative cooling, contributing towards warmer conditions inland.
- March is likely to be dominated by higher air pressure across much of Australia, reducing frontal activity across the south. By April, air pressure is likely to be closer to normal. This also explains why the southeast is likely to be drier during March, but wetter than average in the three month outlook.
- While the above average autumn rainfall forecast for the southeast of the country is likely to be welcome particularly in areas suffering from mid- to long-term rainfall deficiencies, recovery is likely to require a significant period of above average rainfall.
- 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.
