Tide predictor

Harmonic prediction (Schureman / NOS method) computed in the browser from NOAA CO-OPS constituents. Not for navigation. Astronomical tide only, no weather.

Station or ID Datum Units Date Days station local time overlay NOAA official

High / low water

Predicted height drag / wheel to pan and zoom, hover for value

predictionNOAA officialdaylightnow

Spring / neap envelope daily range over ±45 days, with moon phase (Mf, Mm and the M2/S2 beat)

Constituents

Decomposition the biggest terms over the selected window, and their sum

Phasor view each constituent as a rotating vector f·H at angle V+u−κ; the tide height is the sum of x components. Animates at 600× real time.

Engine: tides.js, a JavaScript port of the constituent definitions in Schureman SP-98 as encoded by pytides and XTide's congen, validated against NOAA predictions in test_tides.js. Data: NOAA CO-OPS metadata API (harmonic constituents and datums).