Ever stared at the ocean and wondered how it all works? Got caught out on a walk, only to find the beach has disappeared? Worry no longer. We’re here to explain tide times, and how to work out the tides for yourself.
What are tides?
Tides refer to the rise and fall of a body of water, particularly oceans – which are strongest at the coastline. They are caused by the gravitational pull between the Earth, moon and sun and how they sit in relation to one another at the time.
On beaches, we see water levels at different heights throughout the day. These are the effects of the tides.
- How to stay safe in the sea with expert advice from the RNLI
- Here's what to do if you get stuck in sinking mud or quicksand
Why is it important to understand tides?
Understanding tide times is very important to avoid the risk of being stranded by the incoming tide. While this may not be an issue at every beach, it’s always worth being aware of.
Tide times and heights are different each day, so it’s important to check the beach forecast each day you’re planning to visit the UK coastline.
If you’re entering the water when the tide is rising, the water could be much deeper than when you went in – and it may take longer to swim back to the shore. You also risk getting cut off by a high tide if you're venturing along another section of coastline. Alternatively, a low tide may reveal sinking mud (also known as quicksand) on a beach, which can be very dangerous if you get stuck in it.
If you do find yourself in trouble, call 999 and ask for the coastguard.
What are tide times?
Tide times tell you when the water at the beach or section of coastline will be at its highest point (high tide) and lowest point (low tide).
What is tide height?
Tide height indicates how high or low the water level will be at high and low tides. These are measured in metres, and help understand the extent of tidal changes across the course of a day.
Why are tide times different each day? How to work out the tides for yourself in the UK
In the UK, we have two high tides and two low tides each day. The interval between the two high tides each day is about 12 hours and 25 minutes, so there is roughly a 6 hour and 12.5-minute gap between high and low tide. If you’re working out tides off the top of your head, a six-hour gap is a rough guide.
If low tide is at 5am, the next low tide will be at around 5pm. The alternative tide – in this instance, high tide – will be at the mid-point. High tide, therefore, will always be six hours after low tide, and vice versa. So in this instance, if low tide is at 5am, high tide will be at 11am, the following low tide at about 5pm, and then high tide again at roughly 11pm. To find the accurate tide times, look up your local beach forecast.
This is an example of the exact tide times of Padstow, Cornwall over the course of a few days, to show the intervals between high and low tides.
Day 1:
- Low: 3.18am
- High: 9.11am
- Low: 3.31pm
- High: 9.32pm
Day 2:
- Low: 3.58am
- High: 9.52am
- Low: 4.12pm
- High: 10.16pm
Day 3:
- Low: 4.41am
- High: 10.38am
- Low: 4.56pm
- High: 11.03pm
How do tides work?
Tides are caused by the gravitational pull of the moon and sun and the rotation of the Earth.
Gravity from the moon (and to a lesser extent, the sun) pull water across the Earth’s surface. The Earth spins on an axis, so the oceans on the surface of the Earth are affected by two forces: the moon’s gravitational pull and the centrifugal force of the Earth and moon orbiting a common centre of mass. Both cause a tidal bulge at different points in the day, causing two tides.
During a full moon, the Earth, moon and sun are all in a line (which is why you can see the moon lit up in its entirety). During this time, you have the greatest gravitational pull – and therefore the biggest tides, called spring tides.
When are spring tides?
Spring tides occur twice a month, coinciding with the new moon and full moon phases. At these points in the month, there is a greater differentiation between high tides and low tides – essentially, the highs are higher and the lows are lower.
These can be quite dangerous, as they cause the tide to come in faster than usual.
Where in the UK has the largest tidal ranges?
The Severn Estuary and the British Channel have the largest tidal ranges in the UK. This is because the Bristol Channel narrows as it comes inland, causing an increase in tidal range. This leads to the Severn Bore, a world-famous tidal surge that travels upstream in a river as a result of an incoming tide. It can be quite the spectacle, attracting surfers and kayakers. A tidal bore is a strong tide that pushes up a river against a current, which can cause impressive waves.
In fact, the Severn Estuary has the second-highest tidal range in the world (after the Bay of Fundy in Canada), reaching 12-14 metres.
- Why is the sea salty when our rivers aren't?
- How well do you know your beach flags? Make sure you can tell the difference with expert advice from the RNLI
- When does a sea become an ocean?
- Cold water shock can be fatal, says first aid expert – here's what it is and how to stay safe
Top image: A lifeguard sign warning of fast incoming tides above the beach of Wells-next-the-Sea in Norfolk, England (credit: Getty Images)
