Reading an underwater visibility forecast
Viziato forecasts underwater visibility for coastal waters and the open ocean, updated every day. This guide explains what the forecast figure measures, sets out the app’s seven ratings from Very Poor to Outstanding in meters and feet, and describes what the free map and Viziato Pro each show.
What the visibility figure means
In Viziato, visibility is how far can be seen horizontally through the water. It is given in feet or meters, set in the app’s Settings under Visibility Unit.
How far can be seen depends on how clear the water is. The U.S. Geological Survey describes turbidity as the measure of the relative clarity of a liquid, and notes that turbidity makes water cloudy or opaque. Materials that make water turbid include clay, silt, very small inorganic and organic matter, algae, dissolved colored organic compounds, and plankton and other microscopic organisms.1
The forecast covers the ocean between 60° N and 60° S. It is recalculated once a day, and each day’s run is published at about 07:45 UTC. Every point on the map carries a forecast, rated from Very Poor to Outstanding.
The visibility scale
Each rating covers a fixed band of visibility. The table gives every band in meters and in feet, with the colors the map uses across it.
| Rating | Meters | Feet |
|---|---|---|
| Very Poor | under 2 | under 7 |
| Poor | 2 to 4 | 7 to 13 |
| Fair | 4 to 7 | 13 to 23 |
| Good | 7 to 10 | 23 to 33 |
| Very Good | 10 to 15 | 33 to 49 |
| Excellent | 15 to 20 | 49 to 66 |
| Outstanding | 20 and over | 66 and over |
Each band starts at its lower figure and runs up to its upper figure, which begins the next band: a forecast of exactly 7 meters is rated Good. Feet are converted from the meter bands (1 meter is 3.28084 feet) and rounded to the nearest foot.
The colors run from brown and amber for murky water, through green and teal, to blue for clear water. They are the map’s standard scale. With Viziato Pro, the range of the map’s color scale can be set in Settings to suit local water.
Where good visibility starts on the scale
On this scale, Good covers 7 to 10 meters, about 23 to 33 feet. Very Good, Excellent and Outstanding cover everything from 10 meters, about 33 feet, upward, and Outstanding begins at 20 meters, about 66 feet. The ratings are names for bands of the forecast figure.
The free map and Viziato Pro
Free
Today’s forecast map is free, anywhere from 60° N to 60° S. It gives today’s conditions at any point as a rating from Very Poor to Outstanding. More than 850 popular boat dive sites are pinned on the map, and the daily Top 10 lists the ten clearest of the included dive sites, ranked by forecast visibility, with their visibility figures.
Viziato Pro
Viziato Pro, a monthly or yearly subscription, adds:
- Exact visibility. The exact visibility prediction in feet or meters, with a chart of the days ahead.
- Nine days. The full 9-day forecast, starting today, with a trend chart at any point.
- Visibility alerts. A notification when the forecast at a saved spot reaches the visibility set for it.
Pro also adds GPX import and export, custom map colors and offline access to the last downloaded forecast. The yearly plan starts with a one-week free trial for accounts that have not used one before. The trial becomes a paid yearly subscription unless it is canceled at least 24 hours before it ends.
What makes coastal water less clear
Near the coast, several things can make water less clear:
- Rain and runoff. During a rainstorm, particles from the land are washed into rivers.1
- Algal blooms. Under the right conditions, algae can grow out of control, and some blooms discolor the water.2
Limitations
Forecasts are estimates and can differ from conditions on site. Far from land, the open-ocean forecast shows broad patterns rather than local detail. They are for informational use and are not for navigation or safety decisions.
Get Viziato
Coming soon to the App Store.
The home page has a sample map of South Florida and the Bahamas, the features, how the forecast is made and the plans. Viziato also has pages on dive sites in the Florida Keys and in Southeast Florida.
Sources
- U.S. Geological Survey, Water Science School. “Turbidity and Water.” usgs.gov/special-topics/water-science-school/science/turbidity-and-water
- National Oceanic and Atmospheric Administration. “What is a harmful algal bloom?” noaa.gov/what-is-harmful-algal-bloom
Sources accessed October 4, 2026. The ratings, their bands and the colors are those used in the Viziato app.