It seems a wetter than average winter is in store for most of Australia this year.

The Bureau of Meteorology released its 2020 Winter Outlook today, with most of the country showing an increased likelihood of wetter than average conditions in the coming three months.

The Bureau's manager of long-range forecasting, Dr Andrew Watkins, said most areas of mainland Australia are showing a better than 70% chance of having a wetter than average winter.

“The Winter Outlook for NSW shows a high chance of above average rainfall for inland areas of the state, however the coastal fringe of the NSW is showing no strong push towards wetter or drier than average conditions,” Dr Watkins said.

“Cooler than average days are more likely for western parts of the state, and warmer than average in the east, particularly near the coast.

“Overnight temperatures are likely to be warmer than average for the entire state.”

Dr Watkins aid the preliminary autumn summary predicted daytime temperatures have been very much below average except for the coastal strip.

Overnight temperatures have been closer to average for most of the state and rainfall has been above average across most of the state, particularly inland areas.

Across the whole of the continent, Dr Watkins said parts of northern Australia are also showing no strong push towards wetter than average conditions.

“But this is typically the dry season anyway”, he said.

Dr Watkins said the winter outlook was being largely driven by warmer than average ocean temperatures off north west WA, as well as warm ocean temperatures in the western Pacific.

"Ocean temperatures in the eastern Indian Ocean are currently warmer than normal, and our models are predicting they will warm further throughout the winter months,” he said.

"When warm sea surface temperatures occur closer to Australia, weather patterns shift towards us too, favouring more cloud and rainfall across the country.

"We last saw this happen in 2016, when a strong negative Indian Ocean Dipole formed to the west of Australia. This was the last time we saw tropical moisture from the northern Indian Ocean deliver good winter rainfall to large parts of Australia.

"We aren't guaranteed the same results as 2016, but the warmer ocean temperatures surrounding the continent will push us in the direction of better than average rainfall.

"As always, it's important people use the outlooks in conjunction with all of the Bureau's other tools to make decisions, including the seven-day forecast which will provide details on potential rainfall for the immediate days ahead."

Daytime temperatures throughout the winter months are expected to be cooler than average for much of the southern half of the country, but warmer than average along the eastern seaboard and most of northern Australia.

Overnight temperatures are likely to be warmer than average across the entire country.

"When we look at the expected temperatures, they really fall in line with the expected rainfall conditions,” Dr Watkins said.

"Areas with a higher chance of above average rainfall are also looking at increased chances of cooler than average days because they are more likely to have cloud cover and more evaporative cooling in the coming months.

"Conversely, it means our nights are more likely to be warmer than average, because that cloud cover will prevent heat from escaping during the evenings.”