Dictionary term
Semidiurnal Tide
Direct answer
Semidiurnal Tide: A Semidiurnal Tide is a tidal pattern with two high waters and two low waters of roughly similar height during a lunar day.
A Semidiurnal Tide has two broadly similar highs and lows each lunar day.
A Semidiurnal Tide has two broadly similar highs and lows each lunar day.
A Sun–Earth orientation for seasonal, atmospheric, tidal, and terrestrial terms.Quick reference
- Use when
- Use Semidiurnal Tide for regional tide classification and local daily scheduling from an official station forecast.
- Do not use it for
- Do not assume exact equal heights or six-hour high-to-low intervals; local constituents and weather modify the curve.
- Reference category
- Seasons & Earth Almanac
- Related terms
- Tidal Datum, Diurnal Tide, Astronomical Season, Equinox
The Chapter · Mystery School
Learn to read the sky for yourself
A mystery school of astrology with a worldwide chapter: letters on the chart and the soul, readings under one sky, and a rule of honesty about what the stars can and cannot say.
- The founding letter, with what the school studies and how it meets
- First word each season, when the doors open
- A seat at the gatherings, wherever in the world you are
Reading about Semidiurnal Tide? The chapter is where readers like you meet.
Founding circle · forming now
The list costs nothing. Word of the school and its gatherings, nothing else. Unsubscribe at any time.
The story behind Semidiurnal Tide
Harmonic analysis explained semidiurnal patterns through strong twice-daily lunar and solar constituents.
Semidiurnal Tide in spiritual tradition
Spiritually, semidiurnal tides can invite attention to repeated coastal rhythm without dictating human behavior.
Semidiurnal Tide: fact and faith, kept distinct
This is a factual calendar, astronomy, Earth-science, cultural-history, or observational reference. It can support wonder and practical planning without becoming a claim of fate, spiritual causation, or private revelation.
Semidiurnal Tide in numerology
Semidiurnal Tide is not a numerology claim. Any numbers attached to it should retain their ordinary scientific, calendrical, navigational, or historical meaning unless a separate symbolic interpretation is clearly labeled.
Why Semidiurnal Tide matters
Recognizing the tidal type helps users interpret prediction tables and expected current reversals.
Semidiurnal Tide at work: an example
Many Atlantic coast locations show approximately twelve-hour spacing between successive high waters.
Where interpretation stops
Semidiurnal Tide is presented as sourced astronomy, calendrical, Earth-science, cultural, or instrument-history reference. Definitions should distinguish measured phenomena from civil convention and historical interpretation, preserve location and time dependencies, and avoid turning factual sky data into a deterministic personal claim.
Sources and editorial method
Research references used for this entry include:
- NOAA Tides and Currents Glossary - Operational definitions for tides, tidal currents, ranges, datums, bores, and amphidromic systems.
- Source
- The Great Almanac Dictionary
- Category
- Seasons & Earth Almanac
- Also appears in
- Seasons & Earth Almanac
- Aliases
- None listed
- Last updated
- 2026-07-16
Identify the twice-daily tide pattern
Semidiurnal Tide in a book is one thing; Semidiurnal Tide in your own birth chart is your life. The Oracle casts your real chart and tells you what it means for your love, your work, and your year ahead, in conversation, free.
Speak with the OracleRelated terms
More in Seasons & Earth Almanac
- Subsolar Point
- Tide
- Axial Tilt
- Climatological Normal
- Earth Shadow
- Green Flash
- Midnight Sun
- Obliquity of the Ecliptic
Common questions
What is Semidiurnal Tide?
A Semidiurnal Tide is a tidal pattern with two high waters and two low waters of roughly similar height during a lunar day.
How is Semidiurnal Tide used in an almanac?
Use Semidiurnal Tide for regional tide classification and local daily scheduling from an official station forecast.
What should I avoid when interpreting Semidiurnal Tide?
Do not assume exact equal heights or six-hour high-to-low intervals; local constituents and weather modify the curve.
