Cape Peninsula, South Africa

Forecast the water, not just the weather.

This is theviz, a probabilistic water-clarity forecast for named dive sites across the Cape Peninsula, False Bay and the Overberg coast.

What it does

Underwater visibility on theviz is estimated from several days of swell and wind history, carrying multiple weather models through the calculation. It presents a median estimate, an 80% range and the chance of clearing a chosen visibility threshold rather than one falsely precise number.

What it covers

The service currently covers 26 named shore and nearshore sites from Clifton and Bakoven on the Atlantic seaboard to Cape Hangklip and Moonlight Beach on the Overberg coast. See the coverage list.

Use it responsibly

A visibility forecast is not a dive plan, a weather warning service or navigation advice. Conditions can change quickly and local hazards, access, currents, marine protected-area rules and personal limits always matter. Inspect the site and make conservative decisions on the day.

Why the forecast has memory

Visibility lags the weather: the sea can look calm after a swell while sediment is still suspended. That settling is what theviz models, which is why it can be more useful for visibility planning than a single current swell reading.