The clear and sunny skies are set to continue through to the weekend.
Meteorologist with weatherzone Tom Hough says maximum temperatures are likely to remain relatively high before dipping significantly on Sunday.
"The remainder of Wednesday looks set to feature clear, sunny skies although there could be some cloud later in the day," he said.
"The maximum temperature on Wednesday should hit that 25 degree mark.
"The Thursday minimum temperature is looking to be around 9 degrees with the maximum to be 23 to 24 degrees.
"There is likely to be a touch more cloud around but it will still be mostly sunny, which is the trend for the next few days. We expect the main difference (between the two days) will be the maximum temperature."
Mr Hough said the warmer weather is likely to continue on Friday with a maximum of 25 degrees with a minimum of around 10 degrees.
The clear skies are due to a high pressure system over the north east of NSW, he said.
In some good news for the weekend, there are likely to be mostly sunny skies although the maximum for Saturday could possibly climb as high as 26 degrees, which is three degrees above the average for this time of the year.
However a cold front and trough will move across Victoria and southern areas of NSW late Saturday before clearing in an easterly direction by Sunday.
"This will see the maximum temperature drop, possibly down by as much as 6 or 8 degrees, to around 19 degrees," Mr Hough said.
Seas are likely to be 1 to 2 metres on Wednesday, dropping on Thursday and Friday before climbing again by the weekend.
Winds are likely to pick up later on Wednesday afternoon and probably Friday afternoon and through into Saturday.
The Bureau of Meteorology has cancelled wind warnings for the Hunter, Sydney, Illawarra, Batemans and Eden coasts for Wednesday September 12.