Wind force (Beaufort) to knots
The forecast says force 5, but your wind meter and your kite work in knots. Here is the whole Beaufort scale side by side: wind force, knots, kilometres per hour and metres per second, with the figures from the KNMI, the Dutch weather service.
Force 4 is 11 to 16 knots, force 5 is 17 to 21 and force 6 is 22 to 27. A knot is 1.852 kilometres per hour. So 20 kilometres per hour is almost 11 knots.
01The table
| Force | Knots | km/h | m/s | Kite 75 kg |
|---|---|---|---|---|
| 0 | < 1 | 0–1 | 0–0.2 | – |
| 1 | 1–3 | 1–5 | 0.3–1.5 | – |
| 2 | 4–6 | 6–11 | 1.6–3.3 | too little |
| 3 | 7–10 | 12–19 | 3.4–5.4 | 17 m+ |
| 4 | 11–16 | 20–28 | 5.5–7.9 | 10–15 m |
| 5 | 17–21 | 29–38 | 8.0–10.7 | 8–10 m |
| 6 | 22–27 | 39–49 | 10.8–13.8 | 6–8 m |
| 7 | 28–33 | 50–61 | 13.9–17.1 | 5–6 m |
| 8 | 34–40 | 62–74 | 17.2–20.7 | 4–5 m |
| 9 | 41–47 | 75–88 | 20.8–24.4 | too much |
| 10 | 48–55 | 89–102 | 24.5–28.4 | too much |
| 11 | 56–63 | 103–117 | 28.5–32.6 | too much |
| 12 | 64+ | > 117 | > 32.6 | too much |
Wind force and speeds: KNMI.1 The kite column is this site's rule of thumb, 2.2 × your weight divided by the wind in knots, for a 75 kilo kiter on a twintip. Above 30 knots Kitewind only works with a small kite, and above 40 knots an hour does not count as a session. For a different weight, the full table is at what size kite for what wind.
02An average, not a gust
Wind force is the average wind over ten minutes.1 The gusts within it are stronger. So force 5 on the radio can mean peaks of 25 knots on the water. That is why you look at the gusts in the forecast too, not just at the number from the weather report.
03Converting it yourself
| From | To | How |
|---|---|---|
| knots | km/h | times 1.852 |
| km/h | knots | divided by 1.852 |
| knots | m/s | times 0.514 |
| m/s | knots | times 1.944 |
10 km/h is 5.4 knots, 20 km/h is 10.8, 30 km/h is 16.2 and 50 km/h is 27 knots.
Pick your spot and enter your weight and your kites. You see the wind per hour in knots, with the gusts and what the wind stations are measuring right now.
04Further reading
- How much wind do you need to kitesurf. Why there is no fixed number.
- What size kite for what wind. The full table, from 50 to 100 kilos.
Words in this article
Sources
- KNMI, "Windschaal van Beaufort" (Beaufort wind scale, in Dutch). knmi.nl