Amphidrome: Tide Almanac
iOS app by Shadowfetch · App Store ID 6792598728 · iOS
Amphidrome is a harmonic tide and current almanac that does its math entirely on your device. Every prediction is computed from bundled tidal harmonic constituents — the same physics professional almanacs use — so it works exactly where cell service dies: a back-bay cove, an offshore bank, a canyon river mouth, or airplane mode.
Most tide apps quietly fail without a signal because they fetch predictions from a server. Amphidrome never does. The full constituent dataset ships inside the app, and the prediction engine runs locally for any date, past or future.
What It Does
- Harmonic tide-height prediction for any date, referenced to the chart datum (MLLW) where published
- Tidal-current speed and direction with flood/ebb axis and slack timing
- High and low tide tables, plus slacks and maximum currents
- A day-by-day almanac spanning up to two weeks, with a shareable day sheet
- Sun and moon rise, set, and transit, plus moon phase and illumination
- An interactive tide and current graph you can scrub to read the exact value at any minute
- Datum reference lines (MHHW, MHW, MSL, MLW, MLLW) drawn right on the curve
Fully Offline Map
- A vector coastline and bathymetry map rendered from bundled geometry — no map tiles, no connection
- Coastlines, minor islands, reefs, lakes, and five bathymetric depth contours
- Every station plotted; tap to open its predictions
Thousands Of Stations
- 1,300+ tide stations and 2,200+ current stations with full harmonic constituents
- Search by name, ID, or state; sort by distance; save your regular spots
The Engine
Privacy and support
Privacy information for Amphidrome: Tide Almanac · Support for Amphidrome: Tide Almanac
Questions: shadowfetchapps@gmail.com
Amphidrome: Tide Almanac · App Store ID 6792598728 · Published by Shadowfetch · shadowfetch.com