Tidewell
Where does Tidewell get its tide data, and is it official?
Quick answer
Tidewell is an independent app and is not affiliated with, endorsed by, or produced by any hydrographic office or government agency. It calculates tide predictions from open tidal-constituent data using the same harmonic methods used to produce official tide tables.
Independent, by design
Tidewell is built and maintained independently. It is not the official tide service for any country or port authority, and it does not claim to be — it’s a well-made, honest prediction tool.
The method behind the predictions
Tide predictions come from harmonic analysis of tidal constituents — publicly available scientific data describing how each station’s water level behaves — computed on-device rather than fetched from a live official feed.
Why that matters
Because predictions are estimates rather than a live official reading, always treat them as guidance for planning (beach trips, fishing, surfing) rather than for navigation, diving, or anything safety-critical — for those, use official charts and your local authority.
Independent tide-prediction app. Tide predictions are estimates and must not be used for navigation.