The Beaufort Scale
| Beaufort number (force) | Wind Speed | Wave height (feet) | World Meteorological Organization Descriptions | |
|---|---|---|---|---|
| knots | mph | |||
| 0 | under 1 | under 1 | - | Calm |
| 1 | 1 - 3 | 1 - 3 | 0.25 | Light air |
| 2 | 4 - 6 | 4 - 7 | 0.5 - 1 | Light breeze |
| 3 | 7 - 10 | 8 - 12 | 2 - 3 | Gentle breeze |
| 4 | 11-16 | 13-18 | 3½ - 5 | Moderate breeze |
| 5 | 17-21 | 19-24 | 6 - 8 | Fresh breeze |
| 6 | 22-27 | 25-31 | 9½-13 | Strong breeze |
| 7 | 28-33 | 32-38 | 13½-19 | Near gale |
| 8 | 34-40 | 39-46 | 18-25 | Gale |
| 9 | 41-47 | 47-54 | 23-32 | Strong gale |
| 10 | 48-55 | 55-63 | 29-41 | Storm |
| 11 | 56-63 | 64-72 | 37-52 | Violent storm |
| 12 | 64 and over | 73 and over | 45 and over | Hurricane |
|
Courtesy of British Rear-Admiral, Sir Francis Beaufort 1805 | ||||