Beaufort scale: wind force 0 to 12, and the wind riders go out in
The Beaufort scale sorts the wind into 13 forces, from 0, calm, to 12, hurricane. The table gives each force in knots, mph, km/h and metres per second, with the wave height and the state of the sea. Below it: the force that kitesurfers, windsurfers, sailors and paddlers really go out in, from 262,195 sessions.
Beaufort scale table: force 0 to 12
The wind speed is the mean wind. The wave height is the probable height of well-developed wind waves on the open sea. The sea needs time to build after the wind rises.
| Force | Name | kn | mph | km/h | m/s | Waves | Sea |
|---|---|---|---|---|---|---|---|
| 0 | Calm | < 1 | < 1 | < 2 | < 1 | – | calm, glassy |
| 1 | Light air | 1–3 | 1–3 | 2–6 | 1–2 | 0.1 m | calm, rippled |
| 2 | Light breeze | 4–6 | 5–7 | 7–11 | 2–3 | 0.2 m | smooth, wavelets |
| 3 | Gentle breeze | 7–10 | 8–12 | 13–19 | 4–5 | 0.6 m | slight |
| 4 | Moderate breeze | 11–16 | 13–18 | 20–30 | 6–8 | 1.0 m | slight to moderate |
| 5 | Fresh breeze | 17–21 | 20–24 | 31–39 | 9–11 | 2.0 m | moderate |
| 6 | Strong breeze | 22–27 | 25–31 | 41–50 | 11–14 | 3.0 m | rough |
| 7 | Near gale | 28–33 | 32–38 | 52–61 | 14–17 | 4.0 m | rough to very rough |
| 8 | Gale | 34–40 | 39–46 | 63–74 | 17–21 | 5.5 m | very rough to high |
| 9 | Strong gale | 41–47 | 47–54 | 76–87 | 21–24 | 7.0 m | high |
| 10 | Storm | 48–55 | 55–63 | 89–102 | 25–28 | 9.0 m | very high |
| 11 | Violent storm | 56–63 | 64–72 | 104–117 | 29–32 | 11.5 m | very high |
| 12 | Hurricane | 64+ | 74+ | 119+ | 33+ | 14.0+ m | phenomenal |
mph and km/h are converted from the knots and rounded.
Which Beaufort force do riders go out in?
Sessions recorded with Waterspeed and shared to its leaderboard, January – November 2026, sorted by the force of their wind. The wind is the forecast for the place and time of each session, not a measurement on the water. For each sport: the most common force, its share of the sessions, and the share of sessions with less wind and with more wind.
| Sport | Sessions | Most common force | Share | Less wind | More wind |
|---|---|---|---|---|---|
| Kitesurf | 14,463 | 4 · moderate breeze · 11–16 kn | 49% | 32% | 19% |
| Windsurf | 74,904 | 4 · moderate breeze · 11–16 kn | 45% | 36% | 19% |
| Wing foil | 80,341 | 4 · moderate breeze · 11–16 kn | 44% | 46% | 10% |
| Windfoil | 14,651 | 4 · moderate breeze · 11–16 kn | 38% | 56% | 6% |
| Sailing | 45,414 | 3 · gentle breeze · 7–10 kn | 37% | 45% | 18% |
| SUP | 23,361 | 2 · light breeze · 4–6 kn | 32% | 30% | 39% |
| Kayak | 6,174 | 2 · light breeze · 4–6 kn | 34% | 31% | 35% |
| Rowing | 2,887 | 2 · light breeze · 4–6 kn | 33% | 29% | 38% |
From a force to knots, and to your own sessions
Convert any wind speed with the knots converter: it gives knots, mph, km/h and m/s with the Beaufort force. Waterspeed saves the wind of each session next to your speed and your track, and Pro adds wind alerts.
Questions
What is the Beaufort scale?
The Beaufort scale is a scale of wind force from 0 to 12. Admiral Sir Francis Beaufort of Britain developed it in 1805 to help sailors estimate the wind by what they see. Each force has a name, such as fresh breeze for force 5, and a range of wind speed.
How many forces does the Beaufort scale have?
Thirteen. The scale starts at force 0, calm, and goes to force 12, hurricane.
What is Beaufort force 5 in knots?
Force 5, a fresh breeze, is 17–21 knots. That is about 20–24 mph or 31–39 km/h.
Does the Beaufort scale measure gusts?
The table of the UK Met Office gives a mean wind speed and its limits for each force. So a force describes the mean wind, and the table has no value for gusts.
How do the Beaufort scale and the sea state fit together?
The scale describes the wind by the look of the sea. The UK Met Office gives a sea state and a probable wave height for each force: force 4, for example, is a slight to moderate sea with waves of about 1 metre. These values are for well-developed waves on the open sea.
Which Beaufort force do kitesurfers and windsurfers go out in?
Most often force 4. In 14,463 kitesurf sessions recorded with Waterspeed, 49% had a forecast wind of force 4, which is 11–16 knots. 32% had less wind and 19% had more. In 74,904 windsurf sessions, 45% had force 4.
Which Beaufort force do sailors go out in?
In 45,414 sailing sessions recorded with Waterspeed, the most common forecast wind was force 3, which is 7–10 knots, with 37% of the sessions. 45% had less wind and 18% had more.
How much wind do SUP and kayak paddlers go out in?
In 23,361 SUP sessions recorded with Waterspeed, the most common forecast wind was force 2, which is 4–6 knots, with 32% of the sessions. In 6,174 kayak sessions it was force 2, with 34%.
How do I convert a Beaufort force to knots, mph or km/h?
Read the row of the force in the table. For a single wind speed, use the Waterspeed knots converter: it shows the value in knots, mph, km/h and m/s with its Beaufort force.
Knots, m/s, waves and sea state: UK Met Office · History of the scale: US National Weather Service · Sessions by force: Waterspeed leaderboard