Beaufort scale
Select a Beaufort number to display detailled information.
| Beaufort number | 00 |
| Descriptive tearm | Calm |
| Wind speed (m/sec) | 0 - 0.2 |
| Wind speed (knots) | < 1 |
Summary
Sea like a mirror.
| Beaufort number | 01 |
| Descriptive tearm | Light air |
| Wind speed (m/sec) | 0.3 - 1.5 |
| Wind speed (knots) | 1 - 3 |
Summary
Ripples with the appearance of scales are formed, but without foam crests.
| Beaufort number | 02 |
| Descriptive tearm | Light breeze |
| Wind speed (m/sec) | 1.6 - 3.3 |
| Wind speed (knots) | 4 - 6 |
Summary
Small wavelets, still short but more pronounced; crests have a glassy appearance and do not break.
| Beaufort number | 03 |
| Descriptive tearm | Gentle breeze |
| Wind speed (m/sec) | 3.4 - 5.4 |
| Wind speed (knots) | 7 - 10 |
Summary
Large wavelets; crests begin to break; foam of glassy appearance; perhaps scattered white horses.
| Beaufort number | 04 |
| Descriptive tearm | Moderate breeze |
| Wind speed (m/sec) | 5.5 - 7.9 |
| Wind speed (knots) | 11 - 16 |
Summary
Small waves, becoming longer; fairly frequent white horses.
| Beaufort number | 05 |
| Descriptive tearm | Fresh breeze |
| Wind speed (m/sec) | 8.0 - 10.7 |
| Wind speed (knots) | 17 - 21 |
Summary
Moderate waves, taking a more pronounced long form;many white horses are formed (chance of spray).
| Beaufort number | 06 |
| Descriptive tearm | Strong breeze |
| Wind speed (m/sec) | 10.8 - 13.8 |
| Wind speed (knots) | 22 - 27 |
Summary
Large waves begin to form; the white foam crests are more extensive everywhere (probably some spray).
| Beaufort number | 07 |
| Descriptive tearm | Near gale |
| Wind speed (m/sec) | 13.9 - 17.1 |
| Wind speed (knots) | 28 - 33 |
Summary
Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind.
| Beaufort number | 08 |
| Descriptive tearm | Gale |
| Wind speed (m/sec) | 17.2 - 20.7 |
| Wind speed (knots) | 34 - 40 |
Summary
Moderately high waves of greater lenght; edges of crests begin to break into the spindrift;the foam is blown in well-marked streaks along the direction of the wind.
| Beaufort number | 09 |
| Descriptive tearm | Strong gale |
| Wind speed (m/sec) | 20.8 - 24.4 |
| Wind speed (knots) | 41 - 47 |
Summary
High waves; dense steaks of foam along the direction of the wind; crests of waves begin to topple, tumble and roll over; spray may affect visibility.
| Beaufort number | 10 |
| Descriptive tearm | Storm |
| Wind speed (m/sec) | 24.5 - 28.4 |
| Wind speed (knots) | 48 - 55 |
Summary
Very high waves with long overhanging crests; the resulting foam, in great patches, is blown in dense white streaks along the direction of the wind. On the whole, the surface of the sea takes a white appearance. The tumbling of the sea becomes heavy and shock-like; visibility is affected.
| Beaufort number | 11 |
| Descriptive tearm | Violent storm |
| Wind speed (m/sec) | 28.5 - 32.6 |
| Wind speed (knots) | 56 - 63 |
Summary
Exceptionally high waves (small and medium-sized ships might be lost for a time behind the waves). The sea is completely covered with long white patches of foam lying along the direction of the wind; everywhere the edges of the wave crests are blown into front; visibility is affected.
| Beaufort number | 12 |
| Descriptive tearm | Hurricane |
| Wind speed (m/sec) | > 32.7 |
| Wind speed (knots) | > 64 |
Summary
The air is filled with foam and spray; sea completely white with driving spray; visibility is very seriously affected.
