:: Windspeed table for Conversion of Knots, Beaufort, m/s and km/h.

Knots Bft. m/s km/h Label
Effect on sea
1 0 0 - 0,2 1 Calm
Sea like a mirror
1-3 1 0,3-1,5 1-5 Light Air
Ripples with the appearance of scales are formed, but without foam crests
4-6 2 1,6-3,3 6-11 Light Breeze
Small wavelets, still short, but more pronounced. Crests have a glassy appearance and do not break
7-10 3 3,4-5,4 12-19 Gentle Breeze
Large wavelets. Crests begin to break. Foam of glassy appearance. Perhaps scattered white horses
11-15 4 5,5-7,9 20-28 Moderate Breeze
Small waves, becoming larger; fairly frequent white horses
16-21 5 8,0-10,7 29-38 Fresh Breeze
Moderate waves, taking a more pronounced long form; many white horses are formed. Chance of some spray
22-27 6 10,8-13,8 39-49 Strong Breeze
Large waves begin to form; the white foam crests are more extensive everywhere. Probably some spray
28-33 7 13,9-17,1 50-61 Near Gale
Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind
34-40 8 17,2-20,7 62-74 Gale
Moderately high waves of greater length; edges of crests begin to break into spindrift. The foam is blown in well-marked streaks along the direction of the wind
41-47 9 20,8-24,4 75-88 Severe Gale
High waves. Dense streaks of foam along the direction of the wind. Crests of waves begin to topple, tumble and roll over. Spray may affect visibility
48-55 10 24,5-28,4 89-102 Storm
Very high waves with long over-hanging 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 on a white appearance. The 'tumbling' of the sea becomes heavy and shock-like. Visibility affected
56-63 11 28,5-32,6 103-117 Violent Storm
Exceptionally high waves (small and medium-size ships might be for
a time East to view 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 froth. Visibility affected
64-71 12 32,7-36,9 118-133 Hurricane
The air is filled with foam and spray. Sea completely white with driving spray; visibility very seriously affected