Parts of the Illawarra experienced significant rainfall overnight, with Foxground reporting over 100mm in rainfall.
The Bureau of Meteorology issued a severe thunderstorm warning for heavy rainfall at 10.10pm last night, as a trough brought slow-moving showers and thunderstorms to coastal areas of the Illawarra.
Read more: Watch as brawl erupts in Group Seven clash
By that time, Foxground was already awash, with 69mm in the two hours to 9.30pm.
Readings by Sunday morning showed that Foxground experienced the brunt of the falls, recording 120mm in the 24 hours to 9am Sunday August 6.
Stations along the coast recorded the higher totals, with Bellambi, Mount Pleasant, Russell Vale and Cringila all reporting over 50mm of rainfall.
Rixons Pass weather station, near Woonona, saw 78mm in the 24 hours to 9am.
Falls away from the coast were limited, however, with weather stations west of Lake Illawarra and near Albion Park reporting less than 10mm of rain.
Overnight, the State Emergency Service responded to 15 calls for assistance in the Illawarra, mainly in Figtree, Unanderra and Cordeaux Heights.
The majority were in response to leaking roofs with some tree branches coming down.
No one was severely injured and the damage was not significant for homes or infrastructure.
The severe thunderstorm warning has passed and the Bureau is predicting a top of 17 degrees Celsius for Wollongong, 18 for Albion Park with a 40 per cent chance of rain for the rest of Sunday.
Sign up for our newsletter to stay up to date.