About daily beach pollution forecasts

Find out how we make our daily forecast and how to read it.

Beachwatch monitors swimming sites in the Sydney, Hunter, Central Coast and Illawarra regions for pollution and issues daily forecasts for the water conditions at each site.

During the summer swimming season (October to April), the forecasts are issued before 7:30am, 7 days a week.

Outside of the swimming season (May to September) the forecasts are issued before 9:30am, 7 days a week.

The forecast is updated throughout the day if the conditions change.

How to access the forecast

There are many ways to access our daily beach pollution forecast:

Or select a region from the drop down menu below:

Beaches

Pollution forecast for:

Today's temperature: °C

beaches

Pollution is unlikely, enjoy your swim!

beaches

Pollution is possible, take care.

beaches

Pollution is likely, avoid swimming today!

How to read the forecast

Each site that we monitor has an icon to indicate the likelihood of pollution. If you want more information about a site, hover over its icon and a popup will appear.

Pollution unlikely icon

Pollution is unlikely.

Pollution possible icon

Pollution is possible, so check the water for signs of pollution such as water discolouration or floating debris before swimming.

Pollution likely icon

Pollution is likely, so best to avoid swimming today.

Updated information available

Updated information available. We report on beach closures and pollution incidents, so hover over the icon to see the updated information.

Why and how we forecast

It's tricky to provide up-to-date information on water quality when bacterial results are not available for two to three days after we collect a sample.

We overcome this challenge by predicting the likelihood of pollution using rainfall data.

To do this, we analysed the rainfall and bacterial data collected over the last five years to determine the rainfall thresholds for each swimming location. The rainfall threshold is the amount of rain that falls before the number of bacteria in the water reaches a level that means the water is polluted.

Each morning, we obtain rainfall data from a network of more than 40 gauges. Then we compare how much rainfall has fallen near each swimming site with its rainfall threshold to determine the likelihood of pollution as shown below:

  • Unlikely: rainfall is below the threshold and there is unlikely to be pollution.
  • Possible: rainfall has exceeded the threshold, but not by much. Pollution is possible, so check the water for visual signs of pollution such as water discolouration or floating debris before going for a swim.
  • Likely: rainfall has exceeded the threshold and pollution is likely.