Classify tides based on frequency of their occurrence and height.

1. Semi-Diurnal Tides: The most common tidal pattern featuring two high tides and two low tides each day.

2. Diurnal Tides : There is only one high tide and one low tide during each day. Successive high tides and low tides are approximately of the same height.

3. Mixed Tides : Tides having variation in heights are known as mixed tides.

On the basis of height, tides can be classified as under :

1. Spring Tides : Tides of certain periods of time are unusually lower or higher than normal height. When sun, moon and the earth are in a straight line the tidal range will be high. These are called spring tides.

2. Neap Tides : When the moon is at first and last quarter, the sun and the moon make a right angle to the earth. The attraction of the sun and the moon tends to balance each other. As a result tides with lowest amplitude occur which are termed as neap tides.