Read the Water
Sea temperature, water colour, currents and sea level from satellites and ocean models, laid over the official nautical chart. Stack the layers, fine-tune each one, and see the patterns that move fish.
Every layer shows how old its data is, so you always know what you're looking at.
SST Latest updates through the day from a weather satellite that scans every hour. Where cloud hides the water, the most recent clear reading from the last 12 hours is kept, and you can tap any spot to see its age.
SST Cloud Free is a daily, gap-free picture blended from several satellites: up to about two days old, but complete.
Temp Break lines trace where warm and cool water meet: the places temperature changes fastest, and where predators often patrol.
Isotherms join water of the same temperature. Both are drawn from the same readings as the colours underneath, so they always match.
Chlorophyll shows plankton, the base of the food chain. The edge between rich and clear water is worth a look, much like a temperature break.
Water Clarity shows clean blue water against murkier coastal or river-influenced water.
Animated streaks show which way the surface water is moving and how hard. Surface Currents shows speed as colour, including tide and wind drift.
Current and wave forecasts keep the next two days, so they stay current offline.
Satellite sea-level readings show raised and lowered patches that usually mark warm-core and cold-core eddies, as a colour wash or as labelled rings.
Current Eddies highlights spots where the water is genuinely rotating.
Depth contours and soundings come from the official LINZ nautical chart and show through the data layers.
Tap anywhere to see the depth at that spot. Further offshore, an approximate figure comes from GEBCO's global seafloor map.
Start simple, go deeper when you want to.
One background layer at a time (SST Latest, SST Cloud Free, Chlorophyll or Water Clarity) with four on/off overlays: Temp Break, Isotherms, Zone Edges and Currents.
Every layer. Stack up to four colour layers, each with its own opacity, plus overlays on top. The Layer dock keeps your stack in reach, and you can drag tiles to change which layer sits on top.
Temperature colours stretch across the water on screen, so even small differences stand out. Prefer fixed colours? Set your own range. Both SST layers share one scale, so the same colour means the same temperature.
Satellites and ocean models each publish on their own schedule, so layers can be different ages at the same moment. Each layer shows its age, and a notice appears when newer data arrives while the chart is open.
SST Latest measures the very top of the sea. On calm, sunny days it can read warmer than the water just below until wind mixes it.
Every data provider is credited on our Data sources page.
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