How to Read a Surf Forecast (Beginner's Guide)

A surf forecast tells you how big the waves will be, how powerful they are, which way they’re coming from, what the wind is doing and where the tide sits, hour by hour. To read one, you look at all five together rather than fixating on the height number. A modest swell with a long period, light offshore wind and the right tide will almost always beat a bigger swell with short period and strong onshore wind.

The five numbers that matter

Swell height vs wave face height

The swell height on a forecast is usually the significant wave height of the swell out at sea, not the size of the wave you’ll ride. When that swell reaches shallow water it slows down, stacks up and breaks, and the face you actually see can differ quite a bit from the forecast figure.

As a rough guide:

• Short-period swell often breaks at or below the forecast height.
• Long-period swell often breaks bigger than the forecast height, sometimes noticeably so on exposed reefs and points.
• Sheltered spots (inside bays, behind headlands) often show smaller waves than the number suggests.

Keep units in mind too: 1 m is about 3.3 ft, 1.5 m is about 5 ft, and 2 m is about 6.5 ft. Some regions also describe waves using local scales that run smaller than face height, which is another reason to judge by what you see at your own beach over time.

Swell period

Period is the time in seconds between two wave crests passing the same point. It is the best single indicator of wave energy. Longer-period swells travel from distant storms, carry more energy below the surface and arrive as cleaner, more organised lines. Short-period swells come from nearby wind and tend to be weak and jumbled. We go deeper in swell period explained.

Swell direction

Direction is where the swell is coming from, shown in compass degrees or points (for example 270° or W). Every spot has a swell window: the range of directions it’s open to. A big swell from the wrong angle can miss your beach entirely or get blocked by a headland, while a smaller swell pointed straight at it can be fun.

Wind speed and direction

Wind shapes the surface of the wave. Offshore wind (land to sea) grooms waves and holds them up; onshore wind (sea to land) crumbles them and adds chop. Speed matters as much as direction. For the full breakdown, read offshore vs onshore wind.

Tide

The tide changes the water depth over the sandbar, reef or point, which changes how and where waves break. Some spots work on any tide; many only come alive in a specific window. See how tides affect surf for details.

How the numbers combine

No single number makes a good session. Here is how common combinations tend to play out:

Swell	Period	Wind	Likely result
1 m (3 ft)	12-14 s	Light offshore	Clean, punchy, well-shaped waves
1.5 m (5 ft)	6-7 s	15 kn (28 km/h, 17 mph) onshore	Choppy, messy, hard to read
0.5 m (1.5 ft)	10 s	Glassy	Small but clean; good for longboards and learning
2.5 m (8 ft)	15 s	Light cross-shore	Powerful; experienced surfers only at exposed spots
1 m (3 ft)	9 s	Strong offshore 25 kn (46 km/h, 29 mph)	Waves held up, but hard to paddle in, spray in your eyes

Then layer the tide on top. Even a perfect swell-and-wind combination can be ruined if your break needs mid tide and you show up at dead low.

Check the forecast in 2 minutes

Here’s a simple routine you can run every morning or the night before:

1. Scan the period first. Under about 8 s, expect weaker waves. Around 10 s or more, things get interesting.
2. Check the height against your level. Be honest. Beginners are usually happiest roughly between knee and waist high, about 0.3 to 0.9 m (1 to 3 ft) on the face.
3. Confirm the swell direction suits your spot. If you don’t know your spot’s swell window yet, note the direction every time it’s good and you’ll learn it quickly.
4. Find the wind window. Look for hours with offshore or under roughly 5-8 kn (9-15 km/h, 6-9 mph) of wind. Early mornings are often the cleanest.
5. Overlay the tide. Find when the tide passes through the stage your spot likes.
6. Pick the overlap. The best session is where good wind and the right tide line up while the swell is still running.
7. Look at the cam or the beach. The forecast is a prediction; the ocean is the truth. Watch for 10-15 minutes before you paddle out.

Common beginner mistakes

• Chasing the biggest number. Bigger and more powerful doesn’t mean more fun, especially while you’re learning. Size you can handle beats size that scares you.
• Ignoring period. Two days with the same height can feel completely different. Long-period swells also come in sets with long lulls, which can catch you off guard.
• Forgetting the wind is hourly. A morning that’s glassy can be blown out by early afternoon once the sea breeze kicks in.
• Not checking the tide. Plenty of “flat” or “closing out” days are really just the wrong tide.
• Treating the forecast as gospel. Forecasts beyond a few days can shift. Recheck the evening before and the morning of.
• Skipping safety. Bigger, longer-period swells pull more water through the lineup, which can strengthen currents. Know how to spot and escape rip currents before you rely on any forecast.

Learning your local spot

The fastest way to get good at forecasts is to compare them with what you actually saw. After each session, jot down the swell height, period, direction, wind and tide, plus how the waves really were. Within a few weeks you’ll know that your beach likes, say, a west swell over 10 s on a rising mid tide, and you’ll read forecasts at a glance.

If you’d rather not do the mental math every time, Surfast combines these inputs into a single quality score from Epic to Flat and checks whether the conditions match your skill level, so you can see the best window quickly and still dig into the hourly numbers when you want to.