Relentless rain will soak already sodden areas of eastern Australia this week, with flooding becoming an increasing risk in NSW from Wednesday.

This month has already been exceptionally wet across a large are of eastern NSW thanks to a barrage of rain-bearing systems that have not allowed the landscape to drain before the next burst of heavy rainfall.

As of 9am AEST on Monday, August 18, Sydney’s Observatory Hill weather station had received 215.6 mm of rain. This was close to triple its August monthly average and already puts this month in the top 10 wettest Augusts of all time for Sydney.

The rain has been even more excessive to the north of Sydney, where parts of the Mid North Coast are sitting at around four times their monthly averages. Mount Seaview’s running monthly total of 240.8 mm up to 9am on Monday is well above its August monthly average of 63 mm.

Unfortunately, these waterlogged areas of eastern Australia are in for another run of wet days this week.

A near-stationary upper-level low sitting over NSW will cause rain to soak parts of NSW and Qld every day between Monday and Friday this week. This system will deliver substantial rainfall from central NSW up to southern Qld, with the heaviest rain expected to occur in northeast NSW and southeast Qld, most likely along the coast and ranges.

Image: Modelled atmospheric thickness between the 1000 and 500 hPa pressure surfaces, showing a cut-off upper-level low over NSW on Wednesday.

This week’s impending rain will fall into catchments that are still holding water from recent wet weather, which means flooding will be an elevated risk. This has prompted the Bureau of Meteorology to issue a flood watch for parts of the Mid North Coast and North West Slopes districts in NSW, where minor to moderate flooding is possible from Wednesday into Thursday.

Image: Forecast accumulated rain during the coming week (7 days ending at 10am AEST on Monday, August 25, 2025) according to the ECMWF-HRES model.

Roads in eastern NSW and southern Qld may also become dangerous for driving at times this week, while disruptions to sport fixtures and other outdoor events are also a certainty.

Be sure to check the latest road closures, flood advisories and severe weather warnings in your area throughout the week.