How to Read a Surf Forecast (2027): Swell, Wind, Tides

What does a surf forecast actually show?

Surf forecasts are built on wave models. These take wind fields over the ocean and calculate how much swell is generated, where it travels and when it reaches the coast. Most sites present this as a table or chart in 1- to 3-hour steps.

Typical columns:

A word on height: some sites show open-ocean swell height, others an estimated "surf height" at the beach. If you're unsure, check the site's legend. UK surfers are used to feet; most European sources use metres (1 m ≈ 3.3 ft).

Swell height, period and direction explained

Height: not the whole story

The swell height in a forecast describes the swell in open water. On the beach the breaking wave can be smaller or larger. A swell hitting an exposed beach head-on often breaks bigger than shown; one arriving at an angle into a sheltered bay, or wrapping around a headland, delivers much less.

Most models use "significant wave height" – roughly the average of the highest third of waves. Individual set waves can be noticeably bigger.

Period: the underrated number

The period is the time in seconds between two wave crests. It shows how far the swell has travelled and how much energy it carries.

The catch: a long-period swell can look small on paper but break hard on the beach. 0.8 m at 15 s can feel bigger and heavier than 1.2 m at 8 s. For beginners, a medium period with moderate height is usually the sweet spot.

Swell direction: does it suit the spot?

Every beach faces a particular direction. If the swell comes from that direction, lots of energy arrives. If it comes from the side, it's weakened or blocked. That's why two beaches a few kilometres apart can look completely different on the same day.

On Galicia's Atlantic coast, most swells arrive from the west to north-west. How a particular beach responds depends on which way it faces, any headlands in front of it and whether it sits inside or outside a ría – the deep, fjord-like inlets that shape the Galician coastline.

Wind: offshore, onshore, cross-shore

Wind can turn a great swell into a write-off – or rescue a mediocre one.

• Offshore: wind blowing from the land out to sea. It holds the waves up so they break cleaner and later. Light offshore is the dream. Strong offshore can make take-offs harder because the wave barely picks you up.
• Onshore: wind blowing from the sea onto land. Waves get choppy and break early and messily. Light onshore is often still fine for whitewater practice, but it quickly makes green waves hard work.
• Cross-shore: blowing along the beach. It ruffles the surface and often creates a sideways drift that pushes you down the beach.
• Glassy: no or barely any wind, a mirror-like surface. Common early in the morning or in the evening.

To know what counts as offshore, you need to know which way your beach faces. If it faces west, an easterly wind is offshore. Beginner rule of thumb: under roughly 10–15 km/h, almost any wind direction is learnable. Above about 20–25 km/h onshore, it gets tough.

Tides: why they matter so much in Galicia

Tides change the depth of water over sandbanks and rocks, which changes where and how waves break.

What's the tidal range in Galicia?

Galicia has two high and two low tides a day, roughly six hours apart. The range between them varies with the lunar cycle. Tide tables for the ports of A Coruña and Vigo show spring-tide ranges (around full and new moon) in the order of 3 m to almost 4 m, and neap-tide ranges closer to 1–1.5 m. Your particular beach may differ slightly, so always check the current table for the nearest port.

For comparison: the Mediterranean usually moves only a few tens of centimetres. If you've surfed on Atlantic coasts such as Cornwall or Brittany, big tidal swings won't be new to you. In Galicia the beach can be many metres wider at low tide than at high tide.

What it means for surfing

• At low tide, waves on shallow sandbanks often break faster and hollower, sometimes as close-outs (the whole wave folds at once). Rocks and reefs sit closer to the surface.
• At high tide, waves can get soft or barely break ("too full"), and some beaches develop a shore break right at the water's edge.
• The incoming (rising) tide is a good window at many beach breaks because conditions steadily improve. But this isn't universal – every beach has its favourite tide.
• Currents can change with the tide, especially near river mouths and ría entrances.

For beginners: surf schools often schedule lessons around the tide, not the clock. If your session is early one day and mid-afternoon the next, that's usually why.

Spot exposure: why one beach is pumping and the next is flat

A forecast is valid for a point in the model. Whether your beach gets the swell depends on:

1. Orientation: Does the beach face the swell?
2. Shadowing: Are there islands, headlands or capes in the way?
3. Seabed: Sand, rock or reef – and where the sandbanks currently sit.
4. Position in the ría: The further into a ría you go, the smaller and calmer it usually gets.

That gives you a simple strategy: on small swells, look for open, exposed beaches. On big swells, head for more sheltered bays. It's exactly why surf schools sometimes drive you to a different beach when conditions change.

Stars, bars and colours: what ratings really mean

Almost every site boils conditions down into a rating. Surfline, for example, uses a scale from "Very Poor" to "Epic", which at most spots is calculated by its model from wave height and wind. Surfline itself notes that these model ratings may not account for factors such as tide or wave shape, and that ratings are relative to each spot's potential. Surf-forecast.com uses stars; Windguru uses stars mainly for wind conditions.

For beginners:

• A low rating can be perfect. Small, soft waves often score badly but are ideal for learning.
• A high rating can be too much. "Good" often means powerful, sizeable waves for experienced surfers.
• Compare days, not spots. Ratings help you find the best day of the week at your beach – not decide whether you're ready for it.

Best surf forecast tools and apps

Pro tip: pair a model-based tool (Surfline, Windguru) with real measurements (Puertos del Estado buoys). If the offshore buoy reports much more or less swell than forecast, you know the model is off today.

Beginner thresholds: which conditions suit you?

These are rules of thumb for typical beach breaks. Your instructor knows the spot better and always has the final say.

If you're struggling to get out between sets, that's a clear sign it's too big for today. For more on staying safe and behaving well in the water, see our surf etiquette guide.

Step by step: a worked forecast for Louro, Galicia

Let's take an invented forecast for a summer's day around Louro, near Muros. The numbers are purely illustrative, not real data for any date.

Example forecast for 10 am:

• Swell: 1.2 m from the north-west, period 11 s
• Wind: 8 km/h from the north-east
• Tide: low at 8.30 am, high at 2.45 pm, medium range

How to read it:

1. Check height and period. 1.2 m at 11 s is a clean, solid swell. For complete beginners on an open beach that's at the upper end, but very doable in the whitewater.
2. Match the direction. A north-west swell hits the open Atlantic coast. A beach that's partly sheltered by headlands or its position near the ría typically gets less of it than fully exposed beaches further north on the Costa da Morte. Exactly how sheltered Louro is on a given swell is something the local surf school will know best.
3. Assess the wind. 8 km/h is light. Whether north-easterly is offshore or cross-shore here depends on the beach's exact orientation – but at this strength it barely matters; the surface will stay fairly smooth.
4. Check the tide. At 10 am the tide has been rising for 1.5 hours. At many beach breaks that's a good window. Conditions may change as it fills towards high tide in the afternoon.
5. Cross-check. A look at the nearest buoy readings and MeteoGalicia's marine forecast shows whether the model is on track.
6. Look in person. Spend 10 minutes on the beach: how big are the sets, where are they breaking, where are the currents, which flag is flying?

Verdict: probably a good learning day, ideally in the morning on the rising tide with your surf-school group. If the period were 15 s and the wind 25 km/h onshore, it would be a very different story.

For more on the region and its beaches, read our guide to surfing in Galicia. For when the Atlantic in northern Spain tends to be most beginner-friendly, see the best time to surf in Spain.

Common forecast-reading mistakes

• Only looking at height. Without period and wind, the number is almost meaningless.
• Using one regional forecast for everywhere. Every beach reacts differently.
• Ignoring the tide. In Galicia, one hour can make the difference between perfect and unsurfable.
• Planning five days ahead. Accuracy drops with each day; the next 1–3 days are usually the most reliable.
• Trusting the rating blindly. Stars reflect quality for an average surfer, not suitability for beginners.
• Not checking in person. No forecast replaces 10 minutes of watching.

Learn to read forecasts in Galicia with Semesterkur

Forecast reading is best learned from people who see the spot every day. Semesterkur's surf trip to Louro includes a four-day surf course with Abel Lago Watersports, with board and wetsuit included. Ask the instructors why they head out at a particular tide – it's the quickest way to make sense of the numbers. Find out what to expect on the ground in our guide to the surf camp in Galicia, and which wetsuit suits the Atlantic in our wetsuit thickness guide.

All the details for the surf week are on the Galicia surf trip page – it's in German, but your browser's translate function handles it well.

Last updated: November 2026

Sources

• MeteoGalicia: marine forecast
• Puertos del Estado: oceanography and the Portus network
• Pesca de Galicia: tide tables for Galician ports
• Port Authority of A Coruña: tide tables 2025 (PDF)
• Surfline Support: Surf Ratings & Colors
• Surf-forecast.com: Galicia
• Windguru