How a Tide Clock Works

A normal clock follows the Sun. A tide clock follows the Moon.

A regular clock measures the solar day, the time it takes for Earth to rotate so the Sun returns to the same place in the sky. That takes 24 hours.

A tide clock follows the lunar day, the time it takes for Earth to rotate so the Moon returns to the same place in the sky. Because the Moon is also moving in its orbit around Earth, this takes about 24 hours and 50 minutes.

As Earth rotates beneath the Moon, most coastlines experience two high tides and two low tides each lunar day. The time between one high tide and the next is about 12 hours and 25 minutes.

A tide clock shows where you are in the tide cycle, whether it is a rising tide, high tide, falling tide, or low tide.

Once set, it gives a quick visual sense of what the tide is doing right now.

Setting your tide clock

To set your clock, look up the time of the next high or low tide for your location (from a tide forecast website or app like MetService.)

At that moment, turn the hand to point to High Tide or Low Tide.

Your clock will then return to that point every 12 hours and 25 minutes, keeping in sync with the average tidal cycle.

While the Moon is the main driver, tides are also influenced by the Sun, the shape of the coastline, water depth, and weather conditions. Because of this, real tides do not always follow the exact average lunar cycle, and your tide clock may drift slightly from forecast tide times.

It’s good practice to reset the clock about once a month, or whenever you notice it is slightly out of sync. Many people choose to reset their tide clocks at a new or full moon, when the Sun, Earth, and Moon line up and the tidal pattern is most regular.

It’s a lovely ritual.

Stay in rhythm with the sea

Tide clocks offer a beautiful and intuitive way to stay connected to the rhythm of the ocean.

Noticing that “it’s almost high tide, the best time for a swim,” or “it’s low tide, perfect for a walk along the beach” can be a simple reminder to get outside and enjoy the coast.