In short
Beaufort force table in km/h and knots, with land and sea descriptions.
The Beaufort scale is a way of describing wind strength by what it does on land and at sea — useful when a knot number alone does not paint the picture.
| Force | Term | km/h | knots | On land | At sea |
|---|---|---|---|---|---|
| 0 | Calm | 0 | 0 | Smoke rises vertically | Sea like a mirror |
| 1–3 | Light winds | ≤19 | ≤10 | Wind on face; leaves rustle | Small wavelets, glassy |
| 4 | Moderate | 20–29 | 11–16 | Dust/paper lifts; small branches move | Small waves; frequent white horses |
| 5 | Fresh | 30–39 | 17–21 | Small trees sway | Moderate waves; many white horses |
| 6 | Strong | 40–50 | 22–27 | Large branches move; wires whistle | Larger waves; more foam/spray |
| 7 | Near gale | 51–62 | 28–33 | Whole trees move; hard to walk into wind | Sea heaps up; foam streaks |
| 8 | Gale | 63–75 | 34–40 | Twigs break; progress impeded | Moderately high waves; spindrift |
| 9 | Strong gale | 76–87 | 41–47 | Slight structural damage | High waves; dense foam streaks |
| 10 | Storm | 88–102 | 48–55 | Trees uprooted; considerable damage | Very high waves; sea turns white |
| 11 | Violent storm | 103–117 | 56–63 | Very rarely inland — widespread damage | Exceptionally high waves; long foam patches |
| 12+ | Hurricane | ≥118 | ≥64 | Air full of foam/spray; visibility wrecked |