The mild and mostly sunny winter the region has enjoyed so far is expected to end this weekend, with showers and thunderstorms forecast.
While the temperatures will remain reasonable, with tops of about 17 degrees according to Weatherzone, widespread rain is forecast across the Illawarra.
Showers will increase throughout the day on Saturday, particularly in the late afternoon, and build up to a thunderstorm by Sunday morning. Up to 40 millimetres of rain is predicted each day.
Light north-easterly winds are forecast for Saturday but will strengthen and turn south-westerly on Sunday evening.
Showers are expected to hang around throughout the coming week.
Weatherzone is owned by Fairfax Media.