the time interval between high tide and low tide
When spots get two uneven tides a day-one high and low tides-that is called mixed tide. Coastal regions with a diurnal tide experience only one high and one low tide each day. Tidal period is the length of time between successive high or low tides.These tidal periods change from spot to spot, but tides usually have a fundamental period of 24 hours 50 minutes (lunar day), or 12 hours and 25 minutes.hen spots get two uneven tides a day-one high and low tides-that is called mixed tide. Coastal regions with a diurnal tide experience only one high and one low tide each day. Tidal period is the length of time between successive high or low tides.