Both useful and very decorative, it is an original device that may raise a few questions : how does a tide clock work ? Is a tide clock precise ?

To make the functioning of our creations clear to you, you will find herebelow, in a few words and on video, the answers to all these questions.


How does a tide clock work ? Before we explain in details the functioning of a tide clock, it is essential to remind its utility. This kind of clock, as you probably understood, does not show the time but the tide, and more precisely the time remaining before low tide and high tide. A tide clock is a useful device which allows you to know in the twinkle of an eye if the tide is going down or up in your port or surf spot.

After this quick explanation of the utility of a tide indicator, it is now time to explain to you how a tide clock works.

First of all, it is important to outline that these clocks do not function exactly like usual clocks. Indeed, our tide clocks are assembled with a silent and specific quartz mechanism. Why a specific movement ? Simply because tide indicators do not go round the clock in 24h, like a typical clock, but in 12 hours 25 minutes and 14 seconds. This length of time may seem strange to you but it actually corresponds to the average time between 2 high tides and 2 low tides, in zones where tides are mostly regular.


How a tide clock works

To make a tide clock work, all you need to do is insert a AA battery and set your clock on tide times related to the location of your choice. To do so, we invite you to visit our page : how to set a tide clock.

Once your tide indicator is ready to function, all you have to do is follow the position of the clock hand to know the state of the tide. For your information, the tide clock hand goes clockwise. You wish to learn more on how to read the face of a tide clock ? Find out here how to read a tide clock.

To understand better the functioning of a tide clock, we invite you to watch our short explanatory video here.

You now know how a tide clock works. You still have some questions about it ? Let us answer them then : does a tide clock work everywhere ?


Several centuries ago, tide indicators were developed with mathematical calculations based on lunar days. What is a lunar day ? It corresponds to the time that the Moon takes to go round the Earth, that is to say 24h50mn. How come we refer to lunar days and not solar days ? Simply because the Moon plays an important role on tides formation. It is mostly the gravitational forces of the Moon onto the Earth which create more or less strong tides. Scientists realised that during a lunar day, two high tides as well as two low tides get formed in most oceans.
Basically, we get a high tide and a low tide in 12h25mn.

You are wondering how precise a tide clock is ? During a lunar month (29 days), the tide clock is relatively precise according to the true state of the tide !

However, 12h25mn being the average time between two high tides or low tides, it can happen that some days the tide clock undergoes slight intervals during a tide cycle. However, the clock automatically readjusts in the following cycles, therefore these intervals are just temporary.

Those slight intervals may happen locally when natural or atmospheric elements (violent winds, position of the Sun and Moon in relation to the Earth, equinoxes...) come and affect tides. Therefore, tide cycles may be less regular than usual. For instance, an incoming tide can last 6h40mn while an outgoing tide may last 5h45mn, and so obviously they do not last the same length of time.

If you notice intervals in comparison with tide calendars, you must not adjust the clock as you will disrupt its functioning. You just need to reset it twice a year after equinox periods (we invite you to read our article on equinoxes here), periods which trigger strong tides, that is to say on the first day of Spring and first day of Autumn. If intervals keep happening, do not hesitate to contact us either by phone or via our contact form.

These tide clocks do not claim to be as accurate as tide calendars. They mostly aim at giving you the state of the tide so you know the best time to get into the water.

For your information, tide clocks are not adapted to seafaring. Some water activities require more precise and complete tools that provide current information and precisions about tidal coefficients and water levels, which all are essential to seafaring.


You like our creations and wonder if Ocean Clock tide clocks will function where you are ?

By principle, a tide clock works everywhere ! Indeed, a simple battery is necessary to make it work. However, the clock is not adapted to all oceans and seas over the Earth. This clock shows tide times for places where tides are regular. This tide indicator is only adapted to semidiurnal tides. This involves two high tides and two low tides of relatively similar magnitudes that is to say 24h50mn.

To sum it up, check this video to find out where tide clocks work.

We have listed on the map below the geographical zones where tides are semidiurnal and thus adapted to tide clocks. As shown on this map, the tide clock is most suited for a usage on Atlantic Coast. 


At European level, our tide clocks will indicate you the state of the tide on the Atlantic coast from the south of Spain to the border between Germany and Denmark as well as for most coasts of the United Kingdom and Ireland. Other corners of the world are also suited for the use of tide clocks. Indeed, our tide clocks work on almost the entire American east coast, on most of the African continent's coastline, on some Australian beaches and also on all New Zealand's coasts.

However, the tide clock is not adapted to seas such as the Mediterranean and Baltic seas as they have very low water level variations, or no variations at all for some of them. The tide clock will not be accurate on those coasts !

Our tide clocks work where you live ? Then, do not hesitate to have a look at our collection of tide clocks : here

For other precisions like How to read a tide clock, we invite you to consult this page !

How toread a tide clock ?

Play the video

How do youset your clock

Read more