Most parts of NSW will likely endure wetter than average conditions throughout winter, according to the weather bureau.
The Bureau of Meteorology will on Thursday release its winter 2020 outlook and long-range forecasting manager Dr Andrew Watkins said most areas of mainland Australia were 70 per cent likely to experience a wetter than average season.
Dr Watkins said there was a high chance of above average rainfall for inland areas of NSW, but the state's coastal fringe showed no strong push towards wetter or drier than average conditions.
He said the outlook was largely driven by warm ocean temperatures in the eastern Indian Ocean.
"When warm sea surface temperatures occur closer to Australia, weather patterns shift towards us too, favouring more cloud and rainfall across the country," Dr Watkins said in a statement.
Cooler than average days are more likely for western parts of NSW, with warmer than average conditions expected in the east, particularly near the coast.
Overnight temperatures are likely to be warmer than average for the entire state.
"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."