Our data & how we rate sites

• The Scuba Doctor

  Victorian dive site listings and GPS coordinates used to build our register.

• DiveDB

  Additional site listings and descriptions used to cross-check our register.

• Open-Meteo

  Wind, rain, cloud and marine swell forecasts at 3-hour resolution, out to 5 days.

  Licence: CC BY 4.0

• WillyWeather

  Australian tide predictions (high/low times and heights) for coastal sites.

• Bureau of Meteorology — Water Data Online

  Daily river discharge from stream gauges on the catchments that flow onto our dive sites, used to forecast run-off plumes and their effect on visibility.

  Licence: CC BY 4.0

• Geoscience Australia — Marine Sediments (MARS)

  Seabed samples showing how much mud, sand and gravel lies on the bottom at each site, used to work out how easily the seabed gets stirred up and clouds the water.

  Licence: CC BY 4.0

• Geoscience Australia — Australian Coastal Sediment Compartments

  The coastal sediment setting each site sits in, used to fill gaps where the seabed has never been sampled nearby.

  Licence: CC BY 4.0

• Copernicus Sentinel-2 & Sentinel-3

  Satellite imagery used to estimate recent water clarity over each site.

  Licence: Contains modified Copernicus Sentinel data

• Atlas of Living Australia

  Marine wildlife records near each site, and the species name index behind wildlife search.

  Licence: CC BY 4.0 — records remain the property of their data providers

• Parks Victoria

  Marine national park and sanctuary boundaries, used to flag no-take sites.

• DiveScout divers

  Community-submitted sites, dive logs, reviews, photos and hazard reports.

Every site card shows which register that particular site came from. Community-added sites are credited to the diver who submitted them.

Each site gets a green, amber or red rating for the time you're looking at. We rate four things and the worst one decides the colour — a perfect forecast with one dangerous variable is still a bad day to dive.

1. Swell — the size of the ocean waves rolling into the site. This is the single biggest driver of whether an entry and exit is safe, so we use swell height rather than total wave height (which includes local wind chop that a sheltered bay never sees). Sheltered bay sites have swell suppressed entirely; ocean and back-beach sites don't.
2. Wind — we compare wind direction against the direction the site faces. Wind blowing off the land (offshore) flattens the water; wind blowing onto the site (onshore) builds chop and stirs up sand. The same wind speed can be green at one site and red at the one across the bay.
3. Rain — heavy rain pushes runoff and silt into the water, which wrecks visibility at sites near river mouths and drains.
4. Site-specific rules — some sites only work on slack water, a high tide, or a particular wind quarter. Those rules come from the site register and override the general forecast picture.

On top of the rating we show recent water clarity, estimated from the latest cloud-free satellite pass over the site and a model trained on how conditions in the preceding days affect visibility.

The forecast water visibility figure is an informed estimate, not a measurement. It's predicted from the forecast wind, gusts, 24-hour wind run, onshore component, recent rainfall, water temperature and season, using 196 diver visibility reports matched to the weather at the time of each dive. Typical error is ±2.95 m.

Weather, air temperature, cloud, UV and rain come from the Open-Meteo forecast grid nearest each site, rather than an on-site weather station. Swell and water temperature come from Open-Meteo Marine, while coastal tide predictions come from WillyWeather's nearest available station.

Rain that fell days ago, hundreds of kilometres inland, is often what turns the water brown. Every site in DiveScout is scored for how exposed it is to freshwater discharge — based on which river mouth it sits near, how far away it is, how much water that river carries, how much silt it typically brings, and how quickly the surrounding basin flushes. Williamstown and the top of Port Phillip are the most exposed in the state; Wilsons Promontory and the outer Otway coast are barely affected at all.

We then watch the rivers themselves. Daily discharge from Bureau of Meteorology stream gauges, combined with recent and forecast rainfall over each catchment, tells us when a river is running high or is about to. Sites downstream of that river have their visibility forecast lowered for the days the plume is expected to reach them, and the site page explains which river is responsible.

Catchment rainfall runs ahead of the gauge readings, so a large rain event shows up in the forecast before it shows up in the river. Travel time from a catchment to the coast is estimated, not measured.

Seabed composition changes how easily waves and currents cloud the water. We use Geoscience Australia sediment samples where nearby observations exist, and coastal sediment compartments to estimate unsampled sites. DiveScout groups the bottom as mud, sand, gravel or rock, then compares forecast wave energy with the movement threshold for that material. Muddy and sandy bottoms generally stir more easily and settle more slowly than gravel or reef.

Satellite water clarity comes from the most recent usable cloud-free Copernicus Sentinel pass over the site. It is a recent snapshot, not a live reading, so the site card shows its observation date and keeps it separate from the weather-based forecast.

These are modelled estimates. Offshore sediment surveys can be sparse inside bays, and cloud cover can prevent a recent satellite reading, so DiveScout shows when a seabed classification is estimated and does not substitute satellite history for today's conditions.

The numbers behind the colours move with your experience level, because a swell that's fun for an advanced diver is dangerous for someone on their fifth dive. You're currently set to Intermediate.

• Swell above 0.3 m is amber and above 0.6 m is red for you.
• Strong onshore wind downgrades a site well before strong offshore wind does.
• Sites with known current or rips are hidden at your level, and depth and swim-distance limits apply.

The exact weightings, wind-speed bands and the visibility model itself are DiveScout's own work and aren't published in full. See how your level is set.

Forecasts and satellite estimates are predictions, not observations at the water's edge. Wildlife records show what's been seen nearby before, not what you'll see today. Always make your own call on the day, dive within your training, and never dive alone.