What Is a Tide Clock and How Does It Work?

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 around the Earth, 24 hours 50 minutes.  We refer to lunar days and not solar days because the Moon plays an important role in tide formation. It is mostly the gravitational forces of the Moon onto the Earth which create strong tides. Scientists realized that during a lunar day, two high tides as well as two low tides get formed.  Basically, a high tide and a low tide occur in 12 hours 25 minutes. 

During a lunar month (29 days), the tide clock is relatively precise according to the true state of the tide.  However, 12 hours 25 minutes 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.

How Does a Tide Clock Work? 

This kind of clock 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 if the tide is going down or up at your favorite beach or boating location. 

It is important to note that these clocks do not function exactly like usual clocks. Tide indicators do not go around the clock in 24 hours, like a typical clock, but in 12 hours 25 minutes which corresponds to the average time between two high tides and two low tides, in zones where tides are mostly regular, namely the Atlantic coast of North America. 

Once your tide indicator is ready, follow the position of the clock hand to know the state of the tide.

Are Tide Clocks Accurate?

Yes, for the most accurate results, set your tide clock during high tide on the day of a full moon. If done properly, it will display the minimum error for the month. Usually, the discrepancy will be less than 30 minutes and four to five days each month will have a difference as great as 1 hour.

How to Set a Tide Clock?

Obtain a local tide table and a calendar that includes the days of a full moon and a new moon. Most tide clocks will require “AA” or “AAA” batteries and may need the bezel removed to access the dial. On the day of a full moon, you can adjust the dial to reflect the current tide condition and you’re all set!

If you currently own our Cronus Tide Clock, you can follow the steps in this video.

How to Read a Tide Clock?

Tide clocks are read the same way as a traditional clock. Reading clockwise from high tide starting at twelve o’clock, the tide clock will show the tide falling until you reach low tide, which is equivalent to six ‘clock. The tide clock will continue clockwise and show the tide rising from the six o’clock position to the twelve o’clock position indicating high tide. The numbers on the clock that go from 5 to 1 count down the hours until the tide.

Where Do Tide Clocks Work?

Essentially, tide clocks can work anywhere, but may not be practical for certain areas of the world. There are three basic tidal patterns along Earth’s major shorelines: semidiurnal, mixed semidiurnal, and diurnal. Tide clocks are most effective when used in semidiurnal tidal areas (primarily on the Atlantic Coast), which experience two high and two low tides, approximately equal in size every lunar day. Find your tidal pattern here.

Why Are Tides Important?

Being able to predict tides has always been important for people who work out at sea. Commercial fisherman and recreational fishermen use their knowledge of tides and tidal currents to increase their chances of catching fish. Strong tidal waves and the changing of tides can concentrate bait fish that attract the larger species that fishermen prefer to catch.

Recreational boaters can also benefit from knowing the tide because boats can get stuck in shallow water during low tide. It’s also important to know how much a hull submerges into the water because hitting an inanimate object during low tide can cause a leak.

If you enjoy swimming, paddleboarding, surfing, or kayaking, understanding tidal changes will either make or break your day. Strong tidal changes can cause dangerous rip currents that can lead a swimmer further out into the sea and powerful waves can sweep a person beneath the water when kayaking, surfing, or paddleboarding.

Final Thoughts

As you can see, understanding how tides work and knowing when tides change can be beneficial to a wide range of people and professions. Not only is it useful, but it can also be a great gift or decorative piece for your home that will clearly turn the heads of friends and family. You can check out our entire collection of tide clocks or contact us today for more information!

Additional Resources

• What Are Tides and How Do They Work?
• What is a Nor’Easter and Why The Name?
• What is Knot Speed & How Does It Compare to MPH?