About Tide Tracker's Data
Tide Predictions
Tide height values shown on Tide Tracker — including the tide curve, high and low tides, and "Tide Now" — are predicted values calculated by the National Oceanic and Atmospheric Administration (NOAA) using harmonic analysis of astronomical factors (sun, moon, and Earth rotation).
Tide Observations
Some stations (Primary/Harmonic stations) may have sensors, which measure tide heights. Click on the button "Show Observations" to display available preliminary observations. Subordinate stations do not have sensors.
Times Displayed
Times displayed are local at the station selected.
Tide Heights
All tide height values displayed are from Mean Lower Low Water (MLLW).
NOAA station pages
Each tide station page on Tide Tracker links to the official NOAA station home page for that location, where you may find historical observed water levels, preliminary and verified measurement data, and weather- or surge-related deviations from predictions.
Important Note
Tide predictions are provided for general planning and informational use. For critical navigation or safety decisions, always consult official NOAA observations and publications when available.