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The height of the tide at Okha is about 2.5 meters, while the tide in the Bay of Fundy between New Brunswick and Nova Scotia is the highest ranging; between 15 and 18 meters.

The gravitational interaction of the moon, the sun and the earth is responsible for the occurrence of tides. The Sun by virtue of its big size should attract more but owing to its greater distance from the earth it is unable to exert much influence. The moon on the other hand though much smaller in size than the sun is relatively very close to the earth and is thus able to attract more than the sun. Hence, the moon exerts the strongest influence on tides. The tide producing force of the moon is twice as strong as that of the sun.

Tides do not rise to the same height every day. The relative position of the moon and the sun with respect to the earth is responsible for this variation in the height of tides. On the full moon and the new moon, the moon and the sun are almost in a line with the earth. Hence they exert their combined pull on the earth. Therefore on these two days tides are highest and are known as spring tides.

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

Although tides occur twice a day, their interval is not exactly 12 hours. Instead, they occur at regular intervals of 12 hours and 25 minutes. The moon revolves round the earth from west to east and completes one revolution in 29 1/2 days. Therefore at any place on the earth's surface, the moon does not appear crossing the meridian at the same hour every day as it moves a little eastward in 24 hours. It takes 24 hours and 50 minutes for the rotating earth to bring the same meridian vertically below the moon every day. Hence, high tides follow at intervals of 12 hours and 25 minutes.

Generally, tides occur twice a day. But Southampton along the southern coast of England, experiences tides four times a day. This peculiar phenomenon of four tides instead of two is due to the fact that the tidal waters come through the English Channel, as well as through the North Sea at different intervals.

Tides also occur in the arms of the seas known as gulfs. Gulfs with wide fronts and narrow rears experience higher tides. The height of these tides may be ten meters or more. When a gulf is connected with the open sea by a narrow channel, water flows into the gulf at the time of high tide and comes out of the gulf at low tide. This movement of water, inward and outward, is known as tidal current.

When a tide enters the narrow and shallow estuary of a river, the front of the tidal wave appears to be vertical owing to the piling up of the water of the river against the tidal wave and the friction of the river bed. This steep-nosed tide crest looks like a vertical wall of water rushing upstream and is known as a tidal bore. The favorable conditions of tidal bores include strength of the incoming tidal wave, slope and depth of the channel and the river flow. In India tidal bores are common in the Hooghly River.

Tides generally help in making some of the rivers navigable for ocean-going vessels. London and Calcutta have become important ports owing to the tidal nature of the mouths of the Thames and the Hooghly, respectively. Tides also clear away the sediments brought by the rivers and thus retard the process of delta formation. The tidal force may also be used as a source for generating electricity. For example, France and Japan have power stations, which convert tidal energy into electricity.