How to Read a Tide Table

The sea can make the same stretch of coastline look completely different within a few hours. At low tide, a rocky bay might open up into a wide beach, revealing rock pools, sandy paths and places that were underwater earlier in the day. Return later and the route you used to get there may have disappeared beneath the incoming sea.

That is why checking tide times is an important part of planning a coastal walk, exploring rock pools or visiting a beach you have never been to before. A tide table gives you useful information about when the water is expected to reach its highest and lowest points, along with the predicted height of the water.

At first glance, the figures can look a little confusing. Once you understand what they mean, though, you can use them to make better decisions about where to go, when to turn back and whether a particular route is suitable for your plans.

What Is a Tide Table?

A tide table is a list of predicted high and low tides for a particular location and date. You will usually see two important pieces of information alongside each prediction: the time and the height of the tide.

For example, a simplified tide table might look like this:

Tide	Time	Height
Low water	06:15	0.8 m
High water	12:30	4.9 m
Low water	18:45	0.9 m

These are example figures for learning purposes, not a real forecast for a particular beach.

The table tells you that the water is predicted to be at its lowest at 06:15, rise to its highest point at 12:30 and fall again towards another low tide at 18:45.

The times and heights will change from day to day. You should always check the figures for your intended location and date rather than relying on a tide table you looked at previously.

Understanding High Tide and Low Tide

What does high tide mean?

High tide, also called high water, is the point in the tidal cycle when the sea reaches its highest predicted level before beginning to fall.

On some beaches, high tide covers much of the sand and leaves very little room between the water and the cliffs, sea wall or promenade. Elsewhere, it may cover a causeway, hide rocks or block a route around a headland.

This is particularly important if you are walking along the shoreline. A route that looks perfectly straightforward at low tide may become impassable later in the day.

What does low tide mean?

Low tide, or low water, is the point when the sea reaches its lowest predicted level before beginning to rise again.

This is often when you will see the largest area of exposed beach. Rock pools become accessible, sandbanks appear and some coastal routes become temporarily passable.

However, low tide does not automatically mean that a route is safe. Mud, slippery seaweed, loose rocks and deep channels can still present problems. Some areas are also dangerous because the incoming tide can surround them before you have time to return.

Never assume that you can simply walk back the way you came.

How to Read the Times

Tide tables normally use the 24-hour clock. This removes any confusion between morning and evening.

For example:

• 06:20 means 6.20 am.
• 13:45 means 1.45 pm.
• 18:10 means 6.10 pm.
• 23:30 means 11.30 pm.

When planning a walk, check every tide prediction that could affect your outing, including the tide before you arrive and the next high water.

Suppose low water is predicted for 10:00 and high water for 16:15. The tide will generally be rising between those times. If your walk takes you across a beach that becomes covered at high water, you need to work out when to leave that area safely.

Do not assume you have until 16:15 to get back. Water can cover the route well before high tide, particularly around narrow beaches, rocky outcrops and causeways.

Allow a generous margin for walking speed, rest stops, poor visibility, difficult ground and unexpected delays.

How to Understand Tide Heights

The height column is just as important as the time column.

Tide heights are generally shown in metres and indicate the predicted water level relative to a reference level used by the tide prediction service. They do not simply tell you how deep the water will be at the edge of the beach.

For example, a prediction of 5.0 metres does not mean that there will be five metres of water covering the beach where you are standing. The actual depth depends on the shape of the seabed, the slope of the beach and the local reference level.

The height is useful because it helps you understand how far the tide may reach compared with other tides at the same location.

Imagine two days with the following predictions:

• Day A: high water at 12:00, height 3.8 metres.
• Day B: high water at 12:20, height 5.2 metres.

Day B has a higher predicted tide. Depending on the shape of the coastline, that may mean the water reaches further up the beach or covers areas that remain exposed on Day A.

This is one reason why a familiar coastal route can be safe on one day but unsuitable on another.

What Are Spring and Neap Tides?

You will often see references to spring tides and neap tides in coastal forecasts.

Spring tides

Spring tides have a larger difference between high and low water. They occur around the new moon and full moon, when the combined gravitational effects of the Moon and Sun produce a greater tidal range.

At low water, the sea may retreat further than usual. At high water, it may reach further inland.

These conditions can make some beaches and tidal routes more hazardous. A causeway that is exposed for a useful period during a smaller tide may be covered earlier or for longer during a spring tide.

Spring tides do not mean that the weather will be stormy. The term describes the tidal range, not the weather.

Neap tides

Neap tides have a smaller difference between high and low water. They occur around the first and third quarter phases of the Moon.

The sea generally does not rise as high or fall as low as it does during spring tides, although the actual heights vary by location and date.

Neap tides can still create dangerous conditions. A narrow route may be covered, and local currents or rough weather can introduce additional risks.

Neither type of tide should be treated as a guarantee of safe access.

How to Use a Tide Table to Plan a Coastal Walk

Reading the figures is only the first part. The next step is applying them to the ground you intend to cover.

1. Find the correct location

Use a reputable tide prediction service, such as the Met Office’s beach and tide times guide.

Check which location the predictions refer to. Tide tables are often produced for ports or tidal stations, and the nearest listed location may not be right beside your chosen beach.

Local geography can make a difference, so seek local advice if you are unsure whether the predictions apply to your route.

2. Check the date

Tide times change each day. Do not rely on yesterday’s figures or assume that a visit at the same time next weekend will offer similar conditions.

Check the date you are going, and check again before setting out in case your plans or the forecast have changed.

3. Identify the next high tide

Look for the next high-water prediction and note its time and height.

Then consider your route. Will you cross a beach beneath cliffs? Walk around a headland? Visit a tidal island? Explore a cove with only one practical exit?

If rising water could block your return, plan to be clear of that area well before the route becomes unsafe.

4. Work backwards from your return time

Estimate how long the walk will take, including the return journey. Add time for stops, photographs, uneven ground and the possibility that you may need to turn back early.

For example, if a route takes 90 minutes each way, you should not begin it simply because high tide is still two hours away. You need to consider when the route itself becomes unsafe, not just when the tide reaches its highest point.

The relevant time may be much earlier than high water.

5. Check the weather and local warnings

Strong winds, waves and other weather conditions can affect the sea and make exposed coastal routes more hazardous.

Check the weather forecast as well as the tide table. Read warning signs at the access point, and ask a lifeguard, harbour staff member or another knowledgeable local person if the route is unfamiliar.

If you cannot establish whether the route will remain safe, choose another walk.

Why You Cannot Calculate the Tide by Time Alone

It is tempting to assume that the tide rises at a steady rate between low and high water. It does not.

The rate of change varies throughout the tidal cycle. In many locations, the tide changes most quickly around the middle portion of the rise or fall, rather than directly at high or low water.

This means you cannot safely calculate how much time you have left by looking at the clock and dividing the period between low and high tide into equal sections.

Nor can you assume that a particular height corresponds to a safe route without understanding the local beach.

Use tide tables as part of your planning, but keep watching the water when you arrive. If the tide is rising towards your route sooner than expected, leave early rather than trying to make the most of your remaining time.

Common Mistakes When Reading Tide Tables

Checking the time but ignoring the height

Two high tides can occur at similar times but reach different heights. Check both figures, particularly if you are visiting an area that is regularly covered by the sea.

Using predictions for the wrong location

A nearby port may provide a useful guide, but its predicted times and heights may not match conditions at a particular cove or beach exactly.

Assuming low tide means safe access

Low tide may expose a route, but it can also expose mud, deep channels, slippery rocks and other hazards. The route may become dangerous long before high water.

Leaving the return journey until the last minute

A walk that takes an hour to reach a headland may take considerably longer on the way back if the ground is slippery, the light is fading or the route is difficult.

Always allow more time than you think you will need.

Forgetting to check conditions again

The tide table is a prediction, not a guarantee that every part of the beach will behave exactly as expected. Weather, waves and local geography all matter.

Practise Reading a Tide Table

The best way to become comfortable with tide tables is to practise before you need the information for a difficult route.

Find a real tide table for a familiar beach and identify the next high tide, the next low tide and the predicted heights. Work out whether the tide will be rising or falling when you plan to arrive.

Then look at a local map and identify any beaches, headlands or causeways where the changing water could affect your route. Consider what you would do if you arrived later than planned or found the route already covered.

You do not need to be an expert in tidal science to make better decisions. You do need to understand what the figures mean and recognise when you lack enough information to proceed safely.

Final Tip

Before your next coastal walk, check the tide table for your intended location and date, note the next high water and identify any part of your route that could become cut off.

If the timing looks tight, choose a safer route. The sea will still be there another day, and there is no reason to turn a good walk into an emergency.