Rivera Vale

Rivera Vale is a precise, fully offline tidal harmonic almanac for sailors, anglers, harbour masters, and anyone who needs to know what the sea will do next. Enter the harmonic constants for any tide station and the engine immediately synthesises accurate water-level predictions using the same mathematical foundation used by hydrographic offices worldwide. The Almanac dashboard gives you an at-a-glance view of the next high and low water, today's tidal range, mean sea level, and a live nowcast of the current water level. A spring/neap progress ring shows where you stand in the fortnightly cycle, and the tidal regime is classified automatically from the form factor of your station's constituents. The Forecast screen lets you explore the tide curve in detail. Scrub forward or back through the timeline and switch between a 24-hour view, a 48-hour view, or a per-constituent breakdown that shows how each partial tide contributes to the overall prediction. A 14-day spring/neap strip keeps the big picture in view at all times. The Builder lets you construct or fine-tune any tide station from scratch. Custom sliders for amplitude and phase lag across all nine standard partial tides update a live mini curve in real time. Save as many stations as you need, compare them side-by-side in a dual grid, and attach a reference photo from your library or take one on the spot. Everything runs on-device with no account, no subscription, and no internet connection required.