Not an official NOAA app

Tide Alerts is not an official NOAA product. We do not speak for NOAA, and we do not claim to be more accurate than NOAA everywhere.

What we do claim (narrowly)

Predictions use NOAA-style harmonic techniques on local observations where we have them. That is typically more useful than a NOAA subordinate station that only offsets a distant harmonic gauge. Subordinate stations often cannot provide a full curve the way a harmonic station can.

Many stations in the app are public NOAA (or SECOORA, NERACOOS, USGS) sensors. Seeing a NOAA station in the list does not make Tide Alerts a NOAA app.

Observed vs predicted

Wind, surge, ice, and local bathymetry can move real water away from the harmonic prediction. The chart’s observed trace is there so you can see that gap — not to hide it.

We do not use machine learning as the tide engine in this product, and this help site does not invent ML accuracy claims.

Data is provided as-is for awareness. Use official marine forecasts and your own judgment for navigation and safety.