Climate outlook for May to July
Issued 12 April 2018
Climate outlook overview
- The May to July rainfall outlook, issued 12 April 2018, shows the far southeast of Australia is likely to have a wetter than average three months. Parts of northern Australia are also likely to be wetter than average, however, as May-July is the start of the northern Australian dry season, very little rainfall is needed to exceed the median. The rest of the country has roughly equal chances of a wetter or drier than average three months.
- May to July daytime temperatures are likely to be warmer than average for southern Australia.
- Night-time temperatures are likely to be warmer than average for southern parts of Australia while most of Queensland is likely to have cooler than average nights.
- May days and nights are likely to be warmer for much of the country.
- The El Niño–Southern Oscillation in the tropical Pacific Ocean is neutral, and is expected to remain so for the coming season. The Indian Ocean Dipole (IOD) is also neutral, with the possibility of a negative IOD event from June. With mostly neutral climate drivers, there is no strong push towards broadscale wetter or drier conditions across the country. See the Climate Influences section for more information, or our blog on what to expect when climate drivers are neutral or weak.
Wetter three months likely in far southeast Australia
- A wetter than average May to July is likely for eastern Victoria extending into southeast NSW, and Tasmania. Parts of northern Australia are also likely to be wetter, however, rainfall during the start of the northern Australian dry season (May-September) is typically low, meaning little rainfall is needed to exceed the median. Elsewhere, the chances of a wetter or drier season are roughly equal.
- Historical outlook accuracy for May to July rainfall is moderate over western and southern WA, the southern NT, southeast SA and large parts of the eastern States. See map for more detail.
Warmer days and nights in the south, cooler nights in the northeast
- May to July daytime temperatures are likely to be warmer than average for southern Australia, including southwest WA, southern SA, Victoria and Tasmania. Chances are highest (greater than 80%) in Tasmania.
- Night-time temperatures are likely to be warmer than average for southern Australia while Queensland is likely to have cooler than average nights.
- May days and nights are likely to be warmer for much of the country.
- Historical accuracy for maximum temperatures is moderate to high over most of Australia for May to July. Minimum temperature accuracy is also moderate to high for most of Australia, except parts of southern WA and most of southeast mainland Australia where accuracy is moderate to low.
Climate influences
- Neutral El Niño–Southern Oscillation (ENSO) conditions prevail in the tropical Pacific Ocean. A neutral ENSO state is forecast to persist through the forecast period.
- The Indian Ocean Dipole (IOD) is also neutral, with forecasts suggesting neutral conditions will persist until at least the end of May. For June, the Bureau's climate model suggests an increased likelihood of a negative IOD event. A negative IOD typically results in a wetter than average winter-spring for southern Australia. However, forecast accuracy for the IOD is lower during the autumn compared to other times of the year, and should be viewed with some caution.
- With mostly neutral climate drivers, there is no strong shift in the outlook towards widespread wetter or drier conditions across most of Australia. This does not indicate average rainfall and temperature for Australia. Rather, it means a reduced chance of prolonged or widespread very wet, dry, hot, or cold conditions. Read more in our recent blog on neutral climate drivers and outlooks. Other climate drivers, such as local sea surface conditions or soil moisture, may also have greater influence over the coming months.
- Above average sea surface temperatures in the Tasman Sea, associated with lower pressures over eastern Australia, may be increasing the chance of above average rainfall in the far southeast of the country.
- In addition to the natural drivers such as the El Niño–Southern Oscillation and the Indian Ocean Dipole, 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.
