What causes spring tides?

What is a spring tide?

If you’ve ever visited the Solent and noticed times when the water seems particularly high, while other times it appears unusually low, you’ve likely witnessed a spring tide in action. However, like me, you may not have known what is at play here and exactly what causes spring tides.

A spring tide occurs when the Earth, Moon, and Sun align in a straight line. This happens during two phases of the Moon: the full moon and the new moon. When these celestial bodies align, their gravitational forces combine, creating more extreme tidal conditions. More simply put, the gravitational pull of the Moon and Sun work together to make the ocean’s water bulge more than usual, resulting in:

• Higher high tides: The water level rises higher than during a normal tide.
• Lower low tides: The water level falls lower than usual.

Importantly (and to be totally honest I assumed this was the case!) the term “spring” doesn’t have any relation to the season. Instead it comes from the concept of water “springing forth” due to the increased gravitational pull.

How do Spring Tides impact the solent?

In The Solent, spring tides play a particularly significant role. The Solent is a busy stretch of water, well known for its fast-flowing currents and busy maritime traffic. Due to its unique geography, which includes the narrow strait between the Isle of Wight and the mainland, tides in this area are amplified even under normal conditions.

During a spring tide, these effects are even more noticeable:

• Stronger currents: The water moves much more rapidly during a spring tide. For those navigating the waters, this means more challenging conditions, with faster-flowing currents that require careful planning.
• Higher water levels: As the high tides rise higher, the water in The Solent can reach levels that push closer to the land.
• Larger tidal range: The difference between high and low tide is more extreme. In the Solent, this larger tidal range can expose more of the seabed during low tide and submerge more of the coast at high tide. Both of which can impact where you can go at certain times.

When Do Spring Tides Occur and why does it matter?

Spring tides happen twice a month, during the new moon and full moon phases. This regularity makes them predictable, and tide timetables are available for areas like The Solent, helping you to plan ahead for these more extreme conditions.

For anyone heading out on the solent, especially those with less experience, it’s important to be aware of when these occur. In most cases this is because of the impact a spring tide has on the tide strength which can directly impact your plans for the day, how easy it might be to get to certain places and manoeuvrability of your boat in general.

Find out more information about tide times and weather in various places on the solent.