Climate outlook for May to July
Issued 27 April 2017
Climate outlook overview
- May to July rainfall likely to be below average over the southern two-thirds of mainland Australia.
- May is likely to be drier than average over most of Australia, except far northern Australia and Tasmania.
- Daytime temperatures for May to July are likely to be warmer than average for most of Australia, but cooler than average for the Top End of the NT.
- Night-time temperatures for May to July are likely to be warmer in southwest, central and the far southeast of Australia.
- This outlook is influenced by warming in tropical Pacific sea surface temperatures and a cooler eastern Indian Ocean (see the Climate Influences section for more detail).
Drier May to July likely for southern two-thirds of Australia
- May to July rainfall likely to be below average over the southern two-thirds of mainland Australia. Chances of a drier three months are highest in southeast Australia, where there is a greater than 75% chance that the season will be below average.
- May is likely to be drier than average across most of Australia, except far northern Australia and Tasmania.
- This outlook is influenced by warming in tropical Pacific sea surface temperatures and a cooler eastern Indian Ocean.
- 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.
Warmer days likely for much of Australia, but cooler for NT's Top End
- Daytime temperatures for May to July are likely to be above average for most of Australia, but below average for the Top End of the NT.
- Night-time temperatures for May to July are likely to be warmer for southwest and central Australia, as well as far southeastern parts of Australia. The Top End of the NT is likely to have cooler nights for May to July.
- This outlook is influenced by warming in tropical Pacific sea surface temperatures and a cooler eastern Indian Ocean.
- 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 El Niño–Southern Oscillation (ENSO) remains neutral, but tropical Pacific Ocean waters have been steadily warming since January. The Bureau's climate model suggests some further warming of the tropical Pacific is likely, however, this warming now falls short of El Niño levels. The majority of international climate models surveyed by the Bureau still indicate El Niño is likely to develop later this year. Some caution should be exercised as models have lower accuracy at this time of year in forecasting ENSO. El Niño typically biases Australia's climate towards a drier than average winter-spring, and warmer daytime temperatures in the south. Some El Niño-like effects may still be felt even if an event doesn't fully develop.
- The Indian Ocean Dipole (IOD) is currently neutral. The Bureau's climate model suggests the IOD will remain neutral for at least the next three months, although four out of six international climate models indicate the development of a positive IOD is possible by July. However, slightly cooler than average sea surface temperatures are forecast for the central parts of the tropical Indian Ocean, which may have some effect upon Australian rainfall.
- It should be noted than 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 three months.
- In addition to the natural drivers such as the El Niño–Southern Oscillation and the IOD, Australian climate patterns are being influenced by the long-term increasing trend in global air and ocean temperatures.
- 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.
