Range, not height
Spring and Neap Tides
Next neap alignment
Spring and neap are names for a larger or smaller tidal range, driven in part by whether the Sun and Moon pull in line or at right angles. This page names that alignment. It does not say how high the water will be on a given coast.
This page is not a tide table. It is not for harbors, sailing, or flood timing. A U.S. station forecast comes from measured harmonics, not from phase alone.
How this is calculated
The calculator uses elongation from the same model as the phase tools. Near 0° or 180° the name is spring. Near 90° or 270° the name is neap. The next clocks are the next new or full moon (spring) and the next quarter (neap). Coastline shape, wind, and seafloor are not in the model, so no height in feet is printed.
Questions
Why is there no high-tide clock?
High water is a local series. Two towns a few miles apart can differ by hours. A phase angle cannot replace a tide station.
Does a full moon mean a flood?
No. A full moon often sits near a larger range. Whether that matters on a given shore depends on the station, the weather, and the date in the month. This page does not forecast floods.
Is “spring” the season?
No. The word is older English for a rising or leaping of the water. Spring tides happen all year, near new moon and full moon.