BoM climate outlook: June to August

The Bureau's latest climate outlook – released this week – suggests eastern and southern Australia could be in for a drier than average Winter.

Overview

• The winter climate outlook, issued 30 May 2019, suggests a drier than average winter is likely for much of eastern and parts of southern Australia.
• Daytime temperatures during winter are very likely to be warmer than average.
• With more cloud-free days and nights expected, there is an increased risk of frost in susceptible areas.
• Climate influences include the expected development of a positive Indian Ocean Dipole and a weakening of El Niño-like patterns in the tropical Pacific.

A dry winter likely in the east and parts of the south

• Below average winter rainfall is likely for much of eastern Australia, southeastern SA, and WA's southern coast.
• While the dry signal extends further north, much of this area typically receives little or no rainfall at this time of year.
• Historical outlook accuracy for June to August is moderate to high for most of the country but low in parts of southeast Australia and far northern Queensland. See map for details.

Warmer than average winter days, but frosts possible

• Warmer than average winter days are very likely for most of Australia except in far north Queensland.
• Nights are also likely to be warmer than average overall, however dry soils and the forecast for drier than average conditions could bring more cloud-free nights, increasing the risk of frost in susceptible areas.
• Historical accuracy for winter for maximum temperatures is moderate to high across most of Australia, except parts of the interior and eastern NSW. Minimum temperature accuracy is moderate to high for most of the country except parts of the south. See map for more details.

Climate influences

• The El Niño-Southern Oscillation (ENSO) is currently close to El Niño thresholds in the tropical Pacific, but models expect these El Niño-like patterns to weaken during winter.
• A positive phase of the Indian Ocean Dipole (IOD) is forecast to develop during June and persist until spring. Typically, this means below average rainfall for much of central and southern Australia during winter-spring. The positive Indian Ocean Dipole is likely to be the dominant climate driver for Australia during the winter months.
• The current state of the drivers means that higher than average pressure is likely over southern and possibly eastern Australia. This can act to keep cold fronts further south than normal, thereby reducing winter rainfall to the southern states.
• 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.