Tides are long-period waves that travel through the ocean and appear along the coast as the regular rise and fall of the water. High tide is the higher part of the cycle, low tide is the lower part, and the difference in height between them is the tidal range. Tide height is measured relative to a defined reference level called a datum.
A tide describes vertical water-level change. A tidal current is the horizontal movement of water that can accompany it. Water moving into a bay, estuary, or toward the coast is called a flood current; water moving out is an ebb current. The quieter transition between them is slack current. Current timing does not always match high or low tide exactly, and currents can become especially strong around narrow inlets, straits, and estuary entrances.
Understanding both height and current helps with boating, fishing, surfing, paddling, beach access, and other plans around the water. Tide Guide keeps the tide curve, high and low events, and available current and marine conditions together for the selected station.
Source: NOAA Tides and Water Levels