How to Read a Surf Forecast: Swell, Period, Wind and Tide Explained for Beginners

To read a surf forecast, check four things in order: the swell height, the swell period (the seconds between waves), the wind direction and the tide times for your beach.

It takes two minutes once you know the terms. Below, each one comes with the definition of the people who measure the sea for a living: national weather and ocean services, the French and Dutch tide services, and the help pages of two surf forecast sites. We make soap, not weather models, so the definitions are theirs, and the sources are listed at the end of the article. Still choosing where to go? Start with our best surfing destinations in Europe.

What do the numbers on a surf forecast mean?

They describe the waves at sea (height, period and direction), the wind at the beach and the tide.

Here is each term. The sources are listed at the end of the article.

Term	What it means	What to look for as a beginner
Swell height	Significant wave height: the average height of the highest third of the waves, in open water.	Small numbers. Single waves can be up to double the forecast.
Swell period	The seconds between one wave crest and the next.	6 seconds or less is choppy; 10 or more breaks with more force.
Swell direction	Where the waves come from.	Swell aimed at your beach arrives almost in full; swell running parallel arrives much smaller.
Wind	Onshore blows from sea to land, offshore from land to sea.	Light offshore: clean waves. Onshore: foamy ones.
Tide	The rise and fall of the sea, mostly two highs and two lows a day.	Find the times for your beach and ask which stage it likes.
Spring tide	Higher highs and lower lows than average, around full and new moon.	Take extra care with tide times.
Rating	1 to 10 stars on Surf-Forecast, Very Poor to Epic on Surfline.	A hint. On Surf-Forecast bigger swell means more stars, not easier waves.

 

What do swell height and period tell you?

Height is how big the waves are at sea, and period is the seconds between them, which tells you how much power sits behind that height.

Swell isn't surf yet. Swell is the name for the waves that outrun the storm that creates them. Surf is swell that has arrived in shallow water, where the waves rise up above the surface and break. So the height on your screen is measured at sea: the swell sizes on Surf-Forecast are not the breaking wave height on the beach. It's an average too. The highest individual waves can be up to double the forecast height.

Period is where the power hides. A swell wave, 10 seconds or more, is usually more powerful and will break with more force at the beach than a choppy wave of 6 seconds or less. Surf forecasters give the example of a swell of 2 ft at 20 seconds: on a boat you would barely notice it, yet when it meets shallow water it will likely produce large surf. So 1 m at 14 seconds and 1 m at 6 seconds are two very different days.

Why does swell direction matter?

Because a beach only gets the full swell when the waves are travelling towards it.

If the wave direction is pointing towards the beach, nearly all the offshore wave energy will reach it. Swell running parallel to the coast arrives much lower. Wave buoys report the direction waves come from, so a west swell arrives from the west.

What does your beach want? Its spot guide says. The spot guide for Lahinch, for example, gives west as the best swell direction and east as the best wind (more in our best surf spots in Ireland).

Which wind is best for surfing?

A light offshore wind, blowing from the land out to sea, is the one surfers hope for.

Here's why: offshore winds are good at holding up the crest of the wave and tend to give steeper, clean-faced waves that are good for surfing, while onshore wind tends to blow down the crest of the wave and makes it foamy and poor to surf.

More isn't better, though. A strong offshore can blow you back as you paddle for a wave, and offshore winds can carry inflatables and paddle boards out to sea.

Wind also decides when you surf. If the only light offshore hours are 7 to 9 in the morning, that's your session, and the bag gets packed the night before: wetsuit, towel, dry clothes, something to wash with. It all comes home wet together. A solid 3-in-1 bar for hair, body and face has nothing in it that can leak on the way.

Alarm set. One more check: where will the water be?

How does the tide change the waves?

It depends on the beach: some spots work at every stage of the tide, others only around high or low.

The spot guide for Lahinch promises good surf at all stages of the tide, while surf forecasters also talk about tide-dependent spots that a very high tide slows down.

Most coastal areas get two high and two low tides every 24 hours and 50 minutes, and the same figure holds for the Dutch coast. So tide times slide later each day: low water at 9:00 today means nearer 9:50 tomorrow.

Around full and new moon come spring tides, when high tides are a little higher and low tides are a little lower than average. French tide tables show a coefficient, a measure of the size of the tide. Official tide times come from Shom, the naval hydrographic service, in France and from Rijkswaterstaat in the Netherlands.

One safety note: each year, lots of people get cut off by the tide and need to be rescued. Know which way the water is moving before you walk round a headland.

Can you trust the star ratings, and how far ahead?

Use ratings as a shortcut to the right day, and trust the next few days far more than the end of the forecast.

Surf-Forecast's stars run from 1 to 10 and are based on swell size and character: bigger swell and longer period push the rating up, onshore wind pulls it down. Surfline's ratings run from Very Poor to Epic, and they come with a reminder that there's no substitute for local knowledge.

How far ahead? Surfline scores its first nine days by how closely its 21 swell models agree: the higher the percentage, the less likely the forecast is to change.

So pick the season first with our guide to when to surf in Europe, and keep the forecast for choosing the days. And when it all lines up four days out and you grab a last-minute flight with hand luggage only, one solid 3-in-1 bar for hair, body and face isn't a liquid at airport security.

More in our carry-on wash kit for surf trips.

How do you read a forecast? A worked example

Go through it in the same order every time: height, period, direction, wind, tide.

These numbers are made up for illustration; they are not a forecast for any real beach. Say the forecast for a west-facing beach shows this for Saturday:

• 08:00: swell 0.9 m at 11 seconds from the west, wind 8 km/h from the east, low tide at 07:40.
• 14:00: swell 1.0 m at 11 seconds from the west, wind 26 km/h from the west, high tide at 13:50.

Height: 0.9 m is small, though by the rule from earlier some waves could be double that. Period: 11 seconds is over the 10 second line, so this is swell, not chop. Direction: west swell, west-facing beach, so nearly all of it arrives.

The wind splits the day. At 08:00 it's light and from the land: offshore, the clean option. By 14:00 it's stronger and from the sea: onshore, the foamy option. The tide rises all morning; whether this beach likes that, only the spot guide knows. Verdict: go at 08:00.

Now say Sunday shows 2.5 m at 15 seconds with the same east wind. Plenty of stars, but double 2.5 m is 5 m: watch that one from the sand. And say Monday shows 0.6 m at 5 seconds with a strong west wind: choppy and onshore. Have a lie-in.

What doesn't a surf forecast tell you?

It won't show you rip currents, rocks or crowds, so the last check always happens with your own eyes on the beach.

Rip currents are strong currents running out to sea, which can quickly drag people and debris away from the shallows. If you're caught, the lifesaving advice is not to try to swim against it: stay with your board, wade or swim parallel to the shore, and raise your hand and shout for help.

The standard safety advice for surfers: surf between the black and white chequered flags, go with a mate and know your limits. Flags differ between countries, so ask the lifeguards. Our family surf holidays in Europe list is built around lifeguarded beaches, and when the line-up is busy, surf etiquette matters more than swell period.

After the session: showers, wet kit and washing up

Plan the rinse as part of the session: fresh water for you and your kit, and soap only where the water runs into a drain.

If there's a beach shower, use it for water only: salt and sand off you, your suit and your board. Don't rinse shampoo or soap directly into the ocean or into beach showers that drain to the sea. Lather up later, where the water goes into a drain: at home, at the campsite or in the surf camp bathroom. Here's how to rinse off after a surf.

That bathroom is often small and shared, with everyone's bottles along one shelf. One bar for hair, body and face takes up a corner of it.

Our wetsuit thickness guide and surf trip packing list cover the rest of the kit.

Summary

Read a surf forecast in the same order every time: height for size, period for force, direction for whether the swell is aimed at your beach. Then look for a light offshore wind, check the tide and treat the stars as a hint. To practise close to home, see surfing in the Netherlands and Belgium.

Frequently asked questions

Sources

The facts in this article are based on the sources below, checked in October 2026.

1. Beach forecast and tide times explained. Met Office, 2026.
2. Measurement descriptions and units. NOAA National Data Buoy Center, 2026.
3. JetStream: Waves. NOAA, 2026.
4. What are spring and neap tides?. NOAA National Ocean Service, 2026.
5. Frequency of tides: the lunar day. NOAA National Ocean Service, 2026.
6. Getij. Rijkswaterstaat, 2026.
7. Glossaire: coefficient. Shom, REFMAR, 2026.
8. Horaires des marées officiels. Shom, 2026.
9. Help page and frequently asked questions. Surf-Forecast.com, 2026.
10. Lahinch Strand surf guide. Surf-Forecast.com, 2026.
11. Difference between swell and surf. Surfline, 2026.
12. Surf ratings and colors. Surfline, 2026.
13. Forecast probability. Surfline, 2026.
14. Rip currents. RNLI, 2026.
15. Surfing. RNLI, 2026.