How to Read a Wind Forecast for Kitesurfing

You open a forecast and see:

• Wind: 18 knots
• Gusts: 25 knots
• Direction: SW

Can you ride? Those three numbers alone are not enough to answer that question.

For a kitesurfer, what matters is not only how many knots the forecast shows, but also how steady the wind is, where it is coming from, whether it is building or dropping, what is happening with the weather, how a particular spot works in that direction, and whether the forecast matches what is actually happening at the beach.

The same 20 knots can mean smooth, comfortable wind at one spot and gusty, difficult conditions at another.

That is why you should not simply look at a forecast. You need to know how to read it.

Before a session, there are nine things to check:

• Wind — the main wind speed.
• Gusts & lulls — how much the wind increases and drops.
• Direction — where the wind is coming from.
• Trend — whether the wind is building or fading.
• Weather — thunderstorms, fronts or sudden changes in weather.
• Spot — how the coastline and terrain affect the wind.
• Models — how closely different forecast models agree.
• Live observations — what weather stations are showing right now.
• Actual conditions — what is actually happening at the beach.

Only after that does it make sense to compare the conditions with your riding level and equipment.

In kitesurfing, wind speed is usually measured in knots (kt). 1 knot ≈ 1.85 km/h.

One of the first mistakes beginners make is looking for a universal number: “How many knots do you need for kitesurfing?”

There is no single answer. The same 18 knots mean very different things for a 55 kg rider and a 95 kg rider when it comes to choosing equipment.

Your kite size and design, board, riding level, water conditions and the quality of the wind all matter too.

So: 18 knots describes the wind. It does not yet answer the questions “Which kite should I take?” or “Are these conditions suitable for me?”

There is an important detail that many beginners rarely think about.

When a weather model shows surface wind, it usually refers to wind calculated at a standard height of around 10 metres above the surface.

So when an app shows 20 kt, it does not mean: There will be exactly 20 knots at the height of your hands.

And it does not mean: There will be exactly 20 knots at every point between the water and your kite.

The actual wind profile depends on surface friction, terrain, obstacles, atmospheric stability and other factors.

For a rider, the practical takeaway is this: the number in the forecast is a standardised representation of wind calculated by a model, not a direct measurement of the pull you will feel through the bar.

Compare these two forecasts: A: 20 kt, gusts 23 kt and B: 20 kt, gusts 31 kt.

The main Wind number is the same in both cases. But on the water, they can feel completely different.

In the first case, the difference between the main wind and the gusts is relatively small. In the second, the kite may load up much more strongly in a gust and then lose some of that power again afterwards.

For the rider, that can mean greater changes in speed, edge pressure and body position.

So never look only at Wind. Look at: Wind + Gusts.

Imagine: 18 kt → gusts 21 kt and 18 kt → gusts 29 kt.

In the first forecast, the difference is relatively small. In the second, the potential increases are much larger compared with the main wind speed.

But there is another trap here: creating a rule such as: A difference of up to 5 knots is fine. More than 5 knots is bad.

There is no universal threshold like that.

For example: 12 → 17 kt and 27 → 32 kt both have a five-knot difference. But for a rider, these are completely different wind ranges.

The gust number also does not explain why the wind is gusty. Terrain, buildings, convective activity, a passing weather system or other local processes may all be responsible.

So the gust spread is a useful indicator. But it is not a standalone “ride / don’t ride” rule.

Riders talk a lot about gusts, but difficult wind is not always about the strongest moments.

Lulls — temporary drops in wind speed — can be a problem too.

Imagine the wind is around 18–20 knots, then drops to 12–13, before suddenly returning above 20. For the kite, this means constantly changing power.

During a lull, you may need to work the kite more, adjust your board position or lose speed.

A few seconds later, a gust arrives — and suddenly there is too much power for the body and kite position you were just using.

That is why very inconsistent wind such as: 13 → 25 → 14 → 27 kt can be harder to control than relatively steady: 22 → 25 → 23 → 24 kt.

This is why two days with the same average wind can feel completely different.

Imagine the app shows: 22 knots.

A beginner's first question might be: Which kite should I take? But another question should come first: Where are those 22 knots coming from?

Because wind strength alone tells you nothing about where you will drift if something goes wrong.

The main directions relative to the shore are:

• ONSHORE — from the sea directly towards the beach.
• SIDE-ONSHORE — diagonally from the sea towards the beach.
• SIDESHORE — approximately parallel to the beach.
• SIDE-OFFSHORE — diagonally from the beach towards the sea.
• OFFSHORE — from land towards the sea.

This is why direction matters so much.

• Onshore

The wind blows directly from the water towards land. The advantage is obvious: if something goes wrong, the wind pushes you towards the shore. But that does not automatically make onshore wind safe.

If the beach is narrow and there are rocks, buildings, trees or people nearby, strong onshore wind can push a rider directly towards those hazards. It can also be difficult for a beginner to get far enough away from shore if they cannot yet stay upwind confidently.

• Side-onshore

The wind comes diagonally from the water towards the beach. At many kite spots, this is a convenient direction: you can ride along the coastline while the overall wind direction still has a component pushing you towards land.

• Sideshore

The wind blows approximately parallel to the beach. At a suitable spot, this can also work well, especially when there is enough space for launching and getting onto the water.

• Side-offshore

Part of the wind is directed away from land. If you have a problem with your kite or board, you may gradually drift farther away from shore.

• Offshore

The wind blows from land towards the sea. In open water, this fundamentally changes the consequences of a problem. The kite will not relaunch? Problems with the lines? Lost your board?

You are no longer drifting back towards the beach. You are drifting away from it.

That is why offshore conditions require a completely different risk assessment and may only be suitable at specific spots or where appropriate rescue support is available.

This is where many riders get confused. Wind direction tells you where the wind is coming from, not where it is going:

• N — from the north.
• E — from the east.
• S — from the south.
• W — from the west.

For example: SW means the wind is coming from the southwest. But SW is not automatically a “good” or “bad” direction.

Imagine a beach facing west.

• W → comes directly from the sea → onshore
• N → runs along the beach → sideshore
• E → comes from land → offshore

Now imagine a beach on the other side of an island. The same wind directions create a completely different situation.

So one of the most important rules is: Wind direction is meaningless without understanding the coastline.

Do not memorise: NW is good here.

Understand: What does NW do relative to this particular beach?

Imagine two beaches only 10 km apart. The forecast for both says: NW 20 kt.

At the first spot, the wind may arrive almost directly across open water. At the second, there may be a hill upwind of the beach. The result can be completely different.

Terrain, buildings and even large trees change the airflow.

So it is always useful to ask: What is upwind of my spot?

If there is open sea, that is one situation. If the wind first travels across: a mountain → hotels → trees → a car park → the beach that is something completely different.

This is why local knowledge of a spot cannot be fully replaced by a forecast.

Obstacles disturb airflow. These might include:

• a mountain;
• a hill;
• a cliff;
• a tall hotel;
• a line of trees;
• large buildings.

On the downwind side, you can get areas of weaker, turbulent wind that changes direction. For kitesurfers, this can be particularly difficult around launching and landing areas.

Farther out on the water, the terrain may no longer interfere with the airflow and riders may have 20 knots. But close to the beach, the kite may: lose power → accelerate → change position.

That is why a situation where: “Everyone is riding normally on the water, but the wind at the beach is terrible” is entirely possible.

And it is an important reason not to judge launch conditions only by watching riders 300 metres offshore.

Imagine this forecast:

You arrive at 14:45. You see: 21 knots.

You choose equipment for 21 knots and go out. But your session will not end five minutes later.

In an hour, the forecast is already showing 25 knots. Later, it is close to 30.

So choosing conditions based only on the number at the moment you launch is a mistake.

You need to ask: Where is the wind going?

Compare:

• Forecast A: 17 → 19 → 22 → 25 → 28 kt. The wind is building.
• Forecast B: 24 → 21 → 18 → 15 → 12 kt. The wind is fading.

In the first case, you need to think: Will my equipment and my level still be suitable not only now, but in an hour?

In the second: If the wind continues to drop, will I be able to get back to where I started?

This is especially important during:

• long sessions;
• downwinders;
• riding far from shore;
• sessions at spots where walking back or rescue is difficult.

Do not choose conditions only for the launch. Think about the conditions throughout the entire session.

Windy does not measure future wind. Windy is a weather service that displays and allows you to compare forecasts from different meteorological models, such as ECMWF, GFS and ICON.

So the numbers you see in the app are the results of model calculations, not an exact prediction of how many knots there will be at a particular beach.

A weather model divides the atmosphere into a computational grid and uses physical equations to calculate how weather conditions may change.

But even modern global models use grid sizes measured in kilometres: for example, around 9 km for ECMWF and around 13 km for the global ICON model.

This means a model can represent the broader weather pattern well, but it cannot account in detail for every building, tree, small hill, curve in the coastline or local airflow that may affect the wind directly at the spot.

That is why a forecast should be treated as a calculation of likely conditions, not a promise of a specific wind speed:

• Forecast = model calculation.
• Forecast ≠ exact measurement of future wind.

In Windy, you can switch between different forecast models. For example:

• ECMWF / IFS — the forecasting system of the European Centre for Medium-Range Weather Forecasts.
• GFS — the global American model run by NOAA/NCEP.
• ICON — the model developed by the German Weather Service, DWD.

Other models may be available depending on the region.

They differ in resolution, update frequency, input data and the way they model atmospheric processes.

So it is perfectly normal to see:

• ECMWF: 18 kt
• GFS: 21 kt
• ICON: 16 kt

It does not mean that two of the forecasts are broken. It means there are different calculations of the future state of the atmosphere.

There is no universal answer.

ECMWF will not automatically be the best model at every beach in the world. Neither will ICON.

It is much more useful to learn over time which model tends to work best at your spot with different wind directions.

Windy allows you to compare previous model forecasts with actual weather-station readings through its Observation vs Forecast feature.

After a while, you may start noticing patterns: With NW wind, ECMWF usually underestimates the wind here.

Or: With thermal wind, the model predicts the morning well but often misses the afternoon increase.

That is when you start genuinely understanding the forecast.

It is better not to memorise a rigid rule such as: “Three days is accurate, seven days is not.”

A forecast does not suddenly change from correct to incorrect at a particular point.

Uncertainty gradually increases the farther ahead you look.

So for a kite trip, it is more useful to think like this:

• Today–tomorrow: you can plan a specific session in reasonable detail, but you should still recheck the conditions.
• A few days ahead: useful for planning, but watch whether the forecast changes between updates.
• Around a week ahead: pay more attention to the general weather pattern and agreement between models, and less attention to an exact number such as 23 kt at 15:00.
• Long-range forecast: useful for understanding the trend, but not for deciding which kite you will rig at a specific hour.

One possible reason is a sea breeze.

During the day, land heats faster than water. The air over the land warms and rises, while cooler air from over the sea moves towards the coast. This creates a local circulation.

For a kitesurfer, it might look something like this:

• 09:00 — 8–10 kt
• 11:00 — 11–13 kt
• 13:00 — 16–18 kt
• 15:00 — 20+ kt

That is why a local instructor may tell you: Don’t come at 10 in the morning. The wind will switch on after lunch.

Even though the forecast looks completely uninteresting earlier in the day.

Do not make the next mistake: Hot day = guaranteed afternoon wind.

No. A sea breeze interacts with the wider weather situation.

For example, a strong background offshore flow may interfere with the development or movement of a sea breeze, while a favourable general flow can support it.

Cloud cover, temperature differences and local geography can also affect thermal wind.

So a local rule such as: “In summer it always adds five knots after 2 PM here” should be treated as experience from that particular spot, not a law of physics.

If a significant part of the daytime wind is created by thermal effects, the temperature difference between land and water may weaken as solar heating decreases.

The local circulation weakens with it.

So perfect 20-knot conditions at 16:00 do not guarantee the same 20 knots at 18:30. This is especially important if you:

• have gone a long way downwind;
• are riding far from your launch point;
• chose a small kite for the strongest part of the afternoon;
• are planning to ride back upwind later in the evening.

The same principle applies again: Don’t just look at the current number — look at what is creating the wind and where the trend is going.

One of the most dangerous habits is opening an app, seeing nice green or purple wind colours and ignoring everything else.

Before a session, you should at least check the wider weather situation. Pay particular attention to:

• thunderstorms;
• rain and convective clouds;
• rapid changes in wind;
• an approaching front or squall.

Because: 20 knots of stable wind and 20 knots ahead of a thunderstorm squall are not the same 20 knots.

If the wind is weak but a dark cloud approaches and you suddenly get extra power, that is not the moment to quickly pump a smaller kite.

Thunderstorms can bring rapid changes in wind, and the main danger is lightning.

If you can hear thunder, get off the water and beach and move to safe shelter. Stay there for at least 30 minutes after the last thunder.

For a kitesurfer, the rule should be very simple: Thunderstorm approaching = session over.

If you can hear thunder, there is no safe place on open water.

Most of the time, it is not wrong. It is simply measuring the wind where the station is located. That could be:

• an airport;
• a harbour;
• a rooftop;
• a headland;
• a location several kilometres from the spot;
• a different elevation;
• the other side of a hill.

Imagine: Station: 25 kt.

But there is a mountain between the station and your beach.

Conditions at the beach may be completely different. So the useful sequence is: Forecast → Weather station → Actual conditions at the spot not: Weather station = absolute truth for the whole area.

This is where the forecast ends and reality begins.

Before pumping your kite, stop for a few minutes and look around:

• What kite sizes are riders of roughly your weight using?
• How stable are the kites in the air?
• Are there moments when everyone suddenly loses power or gets overpowered?
• What does the water look like?
• Does the actual wind direction match the forecast?
• Are there clouds or weather systems you were not expecting?
• Is the wind building or fading?

And talk to people who regularly ride at that spot.

Someone telling you: “With NW wind, it is always gusty close to shore but becomes clean 200 metres out.” may be more useful than another ten minutes studying Windy.

This is one of the most common mistakes: Windy says 20 knots — I’ll rig my 12.

Kite size depends on a combination of: rider weight + actual wind + gusts + lulls + board + kite model + riding level + water conditions + changing conditions.

And the last point is especially important: What will the wind be doing not only now, but in an hour?

If the forecast is: 18 → 20 → 25 → 30 kt choosing equipment only for the first 18 knots can quickly become a problem.

The forecast helps you prepare your equipment options. The final choice should be based on the actual conditions.

Once you understand the basic principles, you do not need to conduct a meteorological investigation before every session. Use the same sequence:

1. WIND. How much base wind is there?
2. GUSTS & LULLS. How steady is it?
3. DIRECTION. Where is it coming from relative to the shore?
4. TREND. Will it be 12 or 30 knots in two hours?
5. WEATHER. Are there thunderstorms, fronts or rapid weather changes?
6. SPOT. How do the coastline, hills, buildings and other obstacles affect this direction?
7. MODELS. Do the forecast models agree?
8. LIVE. What are the weather stations showing right now?
9. BEACH. What is actually happening in front of you?
10. YOU. Are these conditions suitable for your level and your equipment?

Only then make the decision.

Windy does not know how confident you are with self-rescue. ECMWF does not know which kite you are going to rig. GFS does not know that yesterday was the first time you managed to stay upwind. A weather station does not know that the wind at your launch is passing over a tall hotel.

All these tools give you data.

But being able to put that data together and make a decision is a riding skill.

And that is one of the things that separates someone who can ride a board from an independent kitesurfer.

Learning to read a forecast means gradually stopping asking: “Is there wind today?” and starting to ask: “What are the conditions today — and are they right for me?”

That is when the forecast becomes genuinely useful.

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