Climate outlook for August to October
Climate outlook overview
- The August to October climate outlook, issued 25 July 2019, suggests a drier than average three months is likely for large parts of Australia.
- August to October daytime temperatures are likely to be warmer than average for much of Australia, with very high chances for the northern half of country.
- Nights are likely to be warmer than average for much of Australia. However, parts of southern Australia and northeast Queensland have roughly equal chances of warmer or cooler nights. With more cloud-free days and nights expected, there is an increased risk of frost in susceptible areas.
- Climate influences include a positive Indian Ocean Dipole (IOD) and an ENSO-neutral tropical Pacific Ocean.
Increased chances of a dry three months
- A drier than average August to October is likely for large parts of the country, including much of eastern and northern Australia and parts of southwest WA and southern SA.
- The month of August is likely to be drier over the tropical north and extending down eastern Queensland and NSW into northern Victoria. Conversely, southeast WA is likely to be wetter than average, with the rest of the country having roughly equal chances of a wetter or drier than average month. It should be noted that August is typically a dry month for the tropical north, apart from Queensland's east coast.
- Historical outlook accuracy for August to October is moderate to high for most of the country but low in parts of southeast and southwest Australia. See map for details.
Warmer August to October days likely
- August to October days are likely to be warmer than average for almost all of Australia. Chances are very high (greater than 80%) for the northern two-thirds of the country. Northeast Queensland, southern Victoria, and western Tasmania have roughly equal chances of warmer or cooler days.
- Nights are also likely to be warmer than average for many areas. However, northeastern Queensland, southern WA, southern SA, western NSW, western Victoria, and northwest Tasmania have roughly equal chances of warmer or cooler nights. Dry soils and the forecast for drier than average conditions mean more cloud-free nights than average are likely, increasing the risk of frost in susceptible areas.
- Historical accuracy for August to October maximum temperatures is moderate to high for most of Australia, except for parts of the Pilbara and south coastal WA. Minimum temperature accuracy is moderate for most of Australia but patchy across the southeast quarter, the southern NT and western WA. See map for more details.
- The El Niño–Southern Oscillation (ENSO) is expected to remain neutral for the remainder of 2019.
- The broad pattern across the Indian Ocean has remained positive IOD-like, with warmer than average sea surface temperatures near Africa and cooler than average waters to Australia's northwest. Indian Ocean Dipole (IOD) index values have been near the threshold for a positive IOD in recent weeks. The latest value has seen the index rise again above the positive IOD threshold.
- Positive Indian Ocean Dipole (IOD) conditions are forecast for the remainder of winter and spring. This typically brings below average rainfall to much of central and southern Australia during winter-spring, which is consistent with the current August to October outlook. The positive IOD is likely to be the dominant climate driver for Australia during the next three months.
- In addition to the natural drivers such as ENSO and the IOD, Australian climate patterns are being influenced by the long-term increasing trend in global air and ocean temperatures.
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