If you were hoping for a sunny end to a scorching summer, think again. 

After a wet start to Saturday, it's going to feel like "Groundhog Day" in Sydney, with rain falls on Sunday potentially reaching up to 40 millimetres and the wet weather then continuing throughout next week.

"It's been quite wet overnight... Rose Bay has had 44 millimetres since 9am yesterday, the highest in a metro area. Manly has had 12 millimetres and the city 6.6 millimetres," said Bureau of Meteorology senior forecaster Neil Fraser.

"After this weekend there will be continuing showers... for Monday, Tuesday, Wednesday, Thursday, Friday... it's going to be Groundhog Day."

Mr Fraser said a small trough sitting off the coast was the cause for the wet period.

"It's good news really. We need the rain to help put some of those fires out." 

Weatherzone meteorologist Craig McIntosh said any storm on Sunday would not be as severe as early Saturday morning, with the rain to remain heaviest in Sydney's eastern suburbs.

"The southerly change interacted with a surface trough, which has caused instability... generally the rainfall that follows is what's coming off the coast," he said.

"It is nothing too out of the ordinary for this time of year. When two different fronts like this converge you get a lot of moisture."

Mr McIntosh said the eastern suburbs could receive anything from 10 to 40 millimetres of rain on Sunday, with Sydney's west receiving about half that amount.

It will also be a very windy weekend.

"We will see some wind today in the wake of the southerly change. Winds will be around 40km/h. We've already seen some gusts of 60km/h at the airport," he said.

"It's going to be a wet finish to summer."

Weatherzone is owned by Fairfax Media, publisher of this website.