How To Read A UK Surf Forecast (Without Driving 90 Minutes To Be Disappointed)

Every UK surfer has done it. The forecast says three feet, the stars are lit up, you drive ninety minutes, and you arrive to a sea that looks like a bowl of grey porridge with a wind blowing across it.

The forecast was not lying. You just read one number out of five. This is how to read all of them, in about a minute, before you put the boards in the car.

The five things a forecast is telling you

Every forecast site dresses it up differently, with colours, stars, arrows and a score out of ten. Underneath, it is the same five things.

1. Wind

Wind is the one that cancels sessions. What matters is not just how hard it is blowing, but which way, relative to the beach.

• Offshore means the wind is blowing from the land out to sea. It holds the wave face up and grooms it. This is what you want.
• Onshore means it is blowing from the sea towards the land. It crumbles the wave from the top and turns it to mush. Same swell, completely different day.
• Cross-shore sits somewhere in between and depends on the spot.

A beach that faces west wants an easterly. A beach that faces north-east wants something from the south-west. Work out which way your local beach faces once and you will never have to think about it again. Light wind from any direction is usually fine. A strong onshore is the reason you were in the car park eating a sandwich.

2. Swell direction

Swell direction is the compass point the waves are coming from, and it only matters in relation to the beach. The swell has to be able to get in.

The Atlantic coasts of Cornwall, Devon and Wales take almost everything the ocean sends, which is why Llangennith works so often. The North Sea needs swell from the north or north-east, which is a much narrower window and the reason the east coast has a reputation for being on or off with nothing in between. The south coast mostly waits for swell wrapping round from the south-west, and on plenty of days it gets none.

If the forecast says big and the direction is wrong for your beach, that is not a surf. That is a very large wave happening somewhere else.

3. Swell period

This is the number most people skip, and the one that tells you the most. Period is the gap in seconds between one wave and the next.

• Under about 8 seconds is wind swell. It was made by local wind, nearby, recently. It is short, choppy and weak.
• 10 seconds and up is groundswell. It was made by a storm a long way away and has had time to sort itself into proper lines. It arrives with more power and better shape.

One metre at 6 seconds and one metre at 14 seconds are not the same thing. The first is a washing machine. The second is a proper day out. If you only learn one thing from this page, learn that.

4. Swell height

The one everyone looks at first, and the least reliable. Height on a forecast is usually the size of the swell offshore, not the size of the wave on your beach. Some spots magnify it. Some shelter from it and give you a fraction. Sites also disagree on how they measure it, so the number is a rumour about the sea, not a measurement of your beach.

Use it for scale, not precision. Learn what "1.5 metres" means at the breaks you actually surf, and ignore the rest.

5. Tide

Plenty of beaches only work on part of the tide. Some are best around mid, some are only worth it on the push, some turn into a dump at high water. The tide does not appear in the swell headline, so it is easy to forget until you are standing on the sand watching a lovely wave break on a dry beach.

The UK Surf Spots guide covers the usual tide windows for the main breaks, and each spot review has a When To Go section.

The sixty-second check

Read it in this order, because that is the order things go wrong.

1. Wind. Is it offshore or light? If it is a strong onshore, stop here and go back to bed.
2. Direction. Can the swell actually reach your beach?
3. Period. Short and choppy, or long and organised?
4. Height. Big enough to be fun, small enough that you will not need to be rescued?
5. Tide. Is your window at a time you can make?

Four out of five is a session. Two out of five is a long drive.

Where forecasts go wrong

• Believing the five-day outlook. The further out, the more it is fiction. Use it to spot a pattern and start planning. Make the call the night before, and again at the car park.
• Trusting a single score. A star rating compresses all five numbers into one and hides the one that matters to you. Look at the numbers underneath.
• Reading only one site. Two sources agreeing is a decent sign. Two disagreeing means it is borderline, and you should find out for yourself.
• Skipping the cam. A forecast is a prediction. A cam is a fact. If there is one near your break, look at it before you leave the house. We keep a list on the cams page.

The cold-water extras

Winter adds a few things the forecast will not show you.

Daylight. By December you get roughly eight hours of it. Check sunrise and sunset, and work back from the dark, not forward from when you feel like getting up.

Wind chill. An offshore wind is great for the wave and miserable for you. It strips heat from wet skin, so a clean offshore morning at 7 degrees air temperature is colder than the number suggests. The sea temperature guide covers what to wear in the water. What you wear after is a separate problem.

The car park. This is where cold-water sessions are actually won or lost. Plan for it as part of the trip: a changing mat towel to stand on, a fisherman beanie or Dome Warmer before anything else goes on, and a heavy layer like the Core Hood you can pull over wet hair. More in How To Change In A Car Park Without Losing The Will To Live.

The honest bit

A forecast is a decision tool, not a promise. You will still get it wrong. You will drive to a flat sea, and you will skip a day that turns out to be perfect, and someone will post a photo of it that evening. That is not a failure of the forecast. It is the hobby.

The skill is not predicting the surf. It is knowing which numbers to trust, and deciding quickly. If you are just starting out, our book How To Surf is the beginner version of all of this. For the rest of the year, the UK Surf Season Guide tells you what each month tends to give you.

Kit built for exactly these conditions, not the brochure version. svrf.uk