Wind for kitesurfing: knots, direction and forecasts

When you judge wind for kitesurfing, look at 3 things: how strong it is, where it comes from and how steady it is. After your course, stick to roughly 10-20 knots, wind blowing from the sea at an angle to the beach, and days when the forecast gusts sit close to the average.

You can make an initial assessment at home from the forecast. Check the conditions for yourself on the beach, because a forecast comes from a model that often misses local obstacles and the sea breeze.

How many knots do you need to kitesurf

Kiters measure wind in knots. 1 knot is 1 nautical mile per hour: 1.852 km/h, about 1.15 mph or 0.51 m/s. Some forecasts show m/s, so a quick rule helps: double the m/s and you are close. 10 m/s is about 19 knots.

How much wind you need to kitesurf depends on your weight, kite size and board. After a course, this is how I'd approach it:

• After your course: get as many hours as you can in roughly 10-20 knots on the right kite size.
• Stronger wind: work up gradually as your kite control and ability to get back to shore improve. I wouldn't go out above 25 knots fresh from a course; around 30 knots requires extensive experience.
• Above 40 knots: don't go out. There is almost no margin for error.

Hours alone don't tell you whether you're ready. Gusts, current and space at the spot matter too. Stay within the manufacturer's wind range for your particular kite, and if you're unsure, talk through the conditions with an instructor before launching.

Kite pull increases quickly as the wind picks up. As a simplified comparison, with the same kite, trim, position and air density, lift grows with the square of the airspeed relative to the kite. A change from 15 to 30 knots gives 4 times the lift; from 15 to 20, almost 1.8 times. While riding, though, the kite moves and its position and trim change, so forecast numbers won't tell you the exact pull you'll feel.

Use the table as a guide to wind strength. Even within 10-20 knots, your kite may not be suitable for the whole range.

Where it blows from: wind direction and the shore

The direction in a forecast always tells you where the wind is coming from. A northwesterly comes from the northwest. Whether it gives you onshore, offshore or side-shore wind depends on the line of the beach. The same northwesterly can be perfect on one beach and blow you out to sea on another.

• Side-onshore, from the sea at an angle to the beach: for me the best direction for a beginner at a suitable spot. You can ride both ways and the wind pushes you towards shore, but still check the current and where you could come ashore.
• Side-shore, parallel to the beach: the wind won't bring you back to shore by itself. You need to be able to get back, understand the current and know where the coastline leads downwind and where you could get out if something goes wrong.
• Onshore, straight at the beach: it pushes you onto the sand. To get away from shore you have to ride upwind (against the wind) straight away, which is hard with waves and current. A small mistake close to the beach ends on the beach.
• Offshore, from the land out to sea: if your kite drops or you can't ride upwind, it carries you away from the beach. Don't ride independently in it after your course, even if you see a boat nearby. Follow your kite manual; a boat doesn't make unsuitable conditions or missing skills safe.

Being scared of ending up downwind with no way back is completely normal after a course. That's why I'd plan my first independent sessions at a suitable side-onshore spot where I could walk back along shallow water or the beach. A way back is as much a part of kitesurfing safety as kite control; check it before launching.

Steady wind or gusty wind

Clean wind keeps the same speed and direction. Gusty wind keeps changing. Clean wind is the easiest and safest to learn in. Light gusts are manageable with some practice, while strong gusts and turbulence make kiting unsafe and not much fun either.

Wind gets smoother the longer it travels over a flat, even surface, typically open sea. Trees, buildings, hills or cliffs break it up. A rough estimate puts turbulence at 7 times the obstacle's height downwind and 3 times its height upwind. For a 20 m high line of trees, that gives 140 m downwind, but turbulence can extend further. Its reach depends on the shape and number of obstacles and the wind speed, so don't use that calculation to decide where it's safe to launch or ride.

I know this from snowkiting at Moldava in the Czech Republic: when the wind comes from the forest and you're close to it, the kite flies in turbulence and it's unpleasant. More distance can help, but reassess the wind at the new location. On water it works the same way, except the forest is a hotel, a pier or a sea wall.

Watch the gusts when you pick a kite size too. A forecast of 15 knots average with gusts of 25 is a big gap, and you could feel much more pull than the average suggests. Choose a size you can manage in the gusts while staying within the manufacturer's range. If your equipment or skills aren't up to it, skip the session.

How to read a wind forecast

In Windguru every time slot has 3 rows that matter: average wind, gusts and direction. Look for the same 3 numbers in any other app, Windy included.

When reading a wind forecast, look across the whole time you plan to be out. Promising signs are:

• an average that doesn't change much over several hours,
• gusts close to the average,
• side-onshore wind at a suitable spot; side-shore only if you can get back and have planned how,
• no heavy rain.

Big jumps in the average, gusts way above it or heavy rain mean changeable conditions. The less experience you have, the harder it is to deal with a change. After a course, I'd skip a day like that.

A forecast is good for deciding whether to go at all, and I really do decide by it. When the forecast for Rügen in Germany looked great, I went, even though it was a long drive there and back. On the beach it's still worth looking at the water and the sky, because some things the model doesn't see:

• Sea breeze builds when the land heats up more than the sea. It often isn't in the forecast and usually peaks in the late afternoon.
• Tall, growing clouds with bands of rain beneath them: wind from them can reach 50 knots, and the gust front runs ahead of the cloud. Get off the water before they reach you.
• A horizontal line of cloud, or a band of rippled water on the horizon, often means a front, and a front always changes the wind.

Final check on the beach

Before you pump up, run through a few things on the sand:

• Turn your face into the wind. When you hear it equally in both ears, you're looking straight where it comes from. Flags and sand help too.
• Compare that with the shore: side-onshore, side-shore or offshore?
• Look at what's upwind of you. Trees, buildings and bushes mean turbulence at launch.
• Work out where the wind will take you if the kite drops, and whether you can walk back in the shallows.
• On a new spot, ask the locals what the wind does there.

I'd choose a spot for the wind and what I want to practise. On a kite safari in Egypt, the crew selects spots according to the wind and forecast and provides rescue. The programme includes morning and afternoon sessions and evening video coaching. Before launching there too, check the direction, gusts and way back to shore against your own ability.