How accurate are these tide predictions?

This is a simplified lunar model — accuracy is roughly ±1–2 hours. Real tides depend on coastline shape, ocean basin resonance, weather, and local geography. Always consult official tide tables from NOAA, the UKHO, or your national hydrographic office before any water activity.

Why does the tool show two high tides per day?

Most coastal locations experience semi-diurnal tides — two highs and two lows every ~24 h 50 min — caused by the Moon's gravitational bulge on both sides of Earth. Some regions have diurnal (one cycle/day) or mixed patterns; the slider lets you approximate a wider range of periods.

What is the tidal period slider for?

The dominant tidal period varies by location: the standard semi-diurnal period is 12.42 h, but estuaries and bays can range from 11 to 14 h. Adjust the slider to better match a known local rhythm.

How does the lunar phase affect tides?

At new moon and full moon (spring tides) the Sun and Moon align, producing larger tidal ranges. At first and third quarter (neap tides) they are at right angles, producing smaller ranges. The tool scales the wave amplitude and shifts the phase offset accordingly.

Can I use this for trip planning?

Yes, as a rough guide. Always cross-reference with official tide tables and local marine forecasts before entering tidal water or planning coastal activities that depend on water level.

Tide Time Estimator

Pick a date to see estimated high and low tide times derived from the lunar phase cycle, plus a 24-hour tide curve.

Select Date

Date

Tidal period 12.42 h

11 hStandard 12.42 h14 h

Lunar phase

Tide type:

Approximation only. Results may differ ±1–2 h from actual tides. Always check official tide tables before any coastal activity.

24-Hour Tide Curve

Tide height High tide Low tide

Estimated Tide Events

Height Reference

Range

High Low

Summary

This tool estimates tidal patterns for a chosen date by modeling the dominant lunar semi-diurnal tide. It calculates the current lunar phase from a known new-moon reference, shifts the tidal timing accordingly, and renders a smooth 24-hour sine curve showing approximate high and low tide windows. Because real tides depend on coastline geometry, ocean depth, weather, and regional amplification, treat every result as a planning approximation rather than an authoritative tide table.

How it works

Select a date using the date picker (defaults to today).
The tool computes the lunar age for that date using the known new-moon epoch of January 6, 2000.
The lunar age determines a phase offset: new and full moons pull tides higher and earlier; quarter moons shift the timing.
A sine-wave model with a 12.42-hour period generates the 24-hour tidal height curve on the canvas.
The four nearest high and low tide events are listed with their estimated times and relative heights.
Adjust the tidal period slider (11–14 h) to match the typical rhythm of your local coastline.

Use cases

Plan a beach visit or surf session around approximate high or low water.
Check whether a tidal flat will be exposed for shellfish gathering.
Estimate safe crossing windows for tidal causeways or estuaries.
Understand how the lunar cycle shifts tide times from day to day.
Teach students about the relationship between the Moon and ocean tides.
Rough-schedule coastal photography for golden-hour low-tide reflections.

Frequently Asked Questions

Last updated: 2026-05-29 · Reviewed by Nham Vu