Tides

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For divers, the effect of tides is important as they can determine the strength and direction of currents and make shallow water navigable.

Slack water at high or low tide is usually the easiest time to dive, but not necessarily the best. Depending on the season, divers can take advantage of a rising tide and clear water flowing into the Atoll to make, for instance, a drift dive through one of the channels.

Spring tides occur between one and three days after a new or full moon and neap tides occur just after the first and third quarters of the moon. During neap tides, the influence of the sun and moon are working against each other, resulting in a minimal tidal range. The approximate times between successive high tides is 12 hours 25 minutes and the interval between spring and neap tides is about 7 1/4 days.

During spring tides, the range is between about 88 cm and 110 cm and during neap tides the range can be as little as a few centimeters. Variations of just a few centimeters can make an immense difference to the strength of tidal currents.

The height of the tide is also affected by the weather. Winds from different directions influence the raising and lowering of the water level and situations of high sea levels on the outside of the Atolls are caused by storm surges and wave set-up. The water also stands higher with a low barometer, to what extent is uncertain.

The times of low and high water must not be considered to coincide with the times of slack water and change of current direction. Inside the Atolls, water often runs in or out long after the tide has turned. Precise and long term data on tidal range and patterns of flow do not exist. Tidal gauges have operated in Male' since 1988 and data collected is now being used to predict tides.

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