marcast

Dive visibility forecast

Know how far you’ll see before you get wet.

MarCast forecasts underwater visibility ten days ahead, for oceans worldwide — everywhere but the far north and the far south. Find the clearest day before you load the boat.

Ask for a TestFlight invite Questions? info@viziato.io

For iPhone, in beta on TestFlight before it reaches the App Store. Free to download; MarCast Pro unlocks all ten days.

MarCast running on an iPhone

Try it

Drag across the map. Read the water.

This is the real map, from a real forecast off New York and New England. Drag across the water for a reading anywhere, in feet or meters. You get the same thing for any ocean, any day.

Loading today’s forecast…

—ft

10-day trend

TodayReading the water

Cloudy skies

No satellite can photograph next Tuesday.

A cloudy week is a normal week.

Next Tuesday hasn’t happened yet, so there is no picture of it for a cloud to spoil. MarCast works the water out ahead from currents, waves and tides, the way a weather forecast works out rain.

Satellites are in here as the record of what this water has been before. A cloudy day leaves a hole in that record. It does not leave one in your forecast.

In the app

Everything you need to pick the day.

Built for divers, spearfishers, snorkelers and the captains who take them out.

  • Ten days ahead

    Slide through the next ten days and watch the water change, so you catch the clear window before it closes.

  • A reading anywhere

    Tap any patch of ocean for visibility in feet or meters, and the trend at that exact spot.

  • Colors for your water

    Dive somewhere that never clears past a few meters? Tell MarCast, and the colors stretch to fit your water — so a good day and a bad day stop looking like the same shade of brown.

  • Clearest in the world

    A daily Top 10 of world-famous dive sites, ranked by forecast visibility.

  • Your spots, your areas

    Star a site, import waypoints straight from your plotter (GPX), or draw a box around a whole reef line and watch it as one spot.

  • Alerts when it clears

    Pick a number. MarCast tells you when the forecast at your spot reaches it.

  • Works offshore

    Download the forecast at the dock and keep reading it after the signal drops.

How it works

Where the number comes from.

Four steps between a satellite and your screen. You do none of them.

  1. A clay satellite with its solar wings out.

    Satellites and ocean models measure the sea, day after day.

    Colour, currents, waves, tides, weather. None of it is a picture of how clear the water is. It is the conditions that decide.

  2. A clay buoy with a disc hanging on a line beneath it.

    People measured how far they could see. MarCast learned from them.

    Real readings taken in the water, set against the conditions on the day they were taken. That is how MarCast knows what today’s sea means for your dive.

  3. A clay globe, the continents pressed up out of a smooth ocean.

    Every day it works out the whole ocean, ten days ahead.

    Not just your spot. Every patch of sea, all in one go, before anybody asks for it.

  4. A clay phone, its screen a plain recessed panel.

    The forecast lands on your phone, and your spot stays yours.

    Your phone takes the whole forecast and reads it where it sits. Where you tap never leaves the device.

Ocean data from the E.U. Copernicus Marine Service, aerosols from the Copernicus Atmosphere Monitoring Service, and weather from ECMWF. Sources and DOIs.

A forecast, not a guarantee. Predictions will sometimes be wrong. MarCast isn’t a navigation or safety tool, so always judge conditions on site.

Plans

Today is free. All ten days are Pro.

MarCast

Free

  • Today’s visibility map, worldwide
  • How clear it is, in words, anywhere you tap
  • Favorite spots

MarCast Pro

Monthly subscription · price shown in the App Store

  • All ten forecast days
  • Exact readings in feet or meters
  • Trend charts at every spot
  • Keeps working offshore, after the signal drops

On the big screen

And an Apple TV app, for the shop wall.

The same forecast, made for a screen on the shop wall: your sites one after another, what the water is doing today, the best day this week, and a QR code your customers can scan to get the app.

In development. The screen here is a mockup — the numbers on it are made up.

It’s on TestFlight first.

MarCast is in beta on TestFlight, Apple’s way of trying an app before it reaches the App Store. Ask for an invite and we will send you one.

Two things worth knowing first. The invite has to go to the address on your Apple Account — that is the only one TestFlight can accept — so tell us that one, even if it is not the address you are writing from. And you install through Apple’s free TestFlight app rather than the App Store.

Ask for an invite

Dive-shop partnerships or press: info@viziato.io

The MarCast app icon