June temperatures have been warmer than usual for most of Australia, especially across the south-east of the country. Sydney had 15 consecutive days above 20 degrees in June, surpassing the previous record of 9 days, set in June 1919.
Across Victoria many sites had their warmest June night on record, including Melbourne, which saw a low of 16.2 °C on the 18th. June has been drier than usual so far in parts of the east and south-west. Elsewhere, rainfall has mostly been close to average. Parts of South Australia and the Interior had well above average June rainfall from a north-west cloudband mid-month.
Soil moisture is currently average to above average across most of the country. In contrast, soils have been drier than average for this time of year for parts of eastern Queensland and Western Australia.
Australia's combined water storages are currently around 66%. While many storages are at capacity, some in the south-east are below 50%. Water storages in southern Australia usually start filling by June. Storage levels in the Murray-Darling Basin, South Australian Gulf and the South West Coast are now higher than last month.
Looking ahead, rainfall for July to September is likely to be below average across much of southern and eastern Australia. Above average rainfall is forecast in parts of the far north - but it is the dry season, so rainfall totals are not expected to be high. There are increased chances of unusually low rainfall for July to September across parts of the south-west and the south-east. While rainfall is likely to be below average, seasonal totals are forecast to reach at least 25 mm in most inland areas, and at least 100 mm in most alpine and coastal regions.
The streamflow forecast for June to August shows high flows are likely across northern Australia, and some sites in the east and south-east. Near median flows are forecast across large areas of eastern Australia. And low flows are likely in much of the south and east, including northern Tasmania.
Looking at temperatures for July to September, days are likely to be warmer than average south of the tropics. Across the north, days are likely to be cooler than average. There are increased chances of unusually high daytime temperatures across the southern half of the country. July to September night-time temperatures are likely to be above average except around parts of the Northern Territory. While nights are likely to be warmer on average, cold spells and frosts can still occur, due to forecast dry conditions and clear skies.
So what's behind our forecast? El Niño has developed in the tropical Pacific, with a strong to very strong event likely. However, a strong El Niño ocean signal does not necessarily mean strong impacts on Australia's climate. Warmer sea temperatures around Australia add more moisture and energy into the atmosphere, which can lead to heavier rainfall during rain events.
