Tideswhen

Tideswhen is a term used in coastal science and navigation to describe the predicted timing of high and low tides at a particular location and date. It refers specifically to the time component of tide predictions—the moments when water levels reach their daily extrema. In practice, tideswhen times are the estimated hours of high tide and low tide, typically expressed in local time and accompanied by an expected water elevation.

The calculation of tideswhen times relies on tidal prediction models that combine astronomical factors, such as the positions and cycles of the Moon and Sun, with historical records of local tides and the influence of coastal bathymetry. Most modern predictions decompose tidal signals into harmonic constituents and sum them to estimate water levels over time. The resulting tideswhen schedule is used to mark when tides will reach their maxima and minima, with uncertainty arising from model precision, atmospheric conditions, and local effects.

Applications of tideswhen information include maritime navigation, harbor and coastal planning, fishing and recreational activities, and flood risk assessment. Agencies and commercial providers publish tables or interactive tools that list tideswhen for ports, beaches, and other coastal sites, sometimes including related metrics such as predicted water height, tide range, and time windows.

Limitations exist: weather systems, such as wind and atmospheric pressure, can modify actual water levels and shift observed high and low tides; storm surge and long-term sea level changes also affect accuracy. As a result, tideswhen predictions are regularly updated and used in conjunction with real-time observations for operational decisions. See also: tide table, tide forecast, astronomical tide, tidal constituents.