Sydney and parts of NSW could collect their best rainfall totals in more than three months according to current forecasts for later this week.

The Bureau of Meteorology says a partly cloudy Wednesday with the chance of showers and a top of 25 degrees for the Harbour City should make way for decent falls on the following three days.

Sydney may collect its best rainfall for several months by the end of the week. Credit:Louise Kennerley

Thursday could see 25-40 millimetres followed by 20-30 millimetres on Friday and 5-10 millimetres on Saturday. The last burst of similar falls over several days was around June 19-20.

Tom Hough, a meteorologist with Weatherzone, says there remains some model disagreement and he predicts lower totals over the three days, but still the best falls for months.