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


Sea like a mirror.

00 - Calm

Beaufort number 01
Descriptive tearm Light air
Wind speed (m/sec) 0.3 - 1.5
Wind speed (knots) 1 - 3


Ripples with the appearance of scales are formed, but without foam crests.

01 - Light air

Beaufort number 02
Descriptive tearm Light breeze
Wind speed (m/sec) 1.6 - 3.3
Wind speed (knots) 4 - 6


Small wavelets, still short but more pronounced; crests have a glassy appearance and do not break.

02 - Light breeze

Beaufort number 03
Descriptive tearm Gentle breeze
Wind speed (m/sec) 3.4 - 5.4
Wind speed (knots) 7 - 10


Large wavelets; crests begin to break; foam of glassy appearance; perhaps scattered white horses.

03 - Gentle breeze

Beaufort number 04
Descriptive tearm Moderate breeze
Wind speed (m/sec) 5.5 - 7.9
Wind speed (knots) 11 - 16


Small waves, becoming longer; fairly frequent white horses.

04 - Moderate breeze

Beaufort number 05
Descriptive tearm Fresh breeze
Wind speed (m/sec) 8.0 - 10.7
Wind speed (knots) 17 - 21


Moderate waves, taking a more pronounced long form;many white horses are formed (chance of spray).

05 - Fresh breeze

Beaufort number 06
Descriptive tearm Strong breeze
Wind speed (m/sec) 10.8 - 13.8
Wind speed (knots) 22 - 27


Large waves begin to form; the white foam crests are more extensive everywhere (probably some spray).

06 - Strong breeze

Beaufort number 07
Descriptive tearm Near gale
Wind speed (m/sec) 13.9 - 17.1
Wind speed (knots) 28 - 33


Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind.

07 - Near gale

Beaufort number 08
Descriptive tearm Gale
Wind speed (m/sec) 17.2 - 20.7
Wind speed (knots) 34 - 40


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.

08 - Gale

Beaufort number 09
Descriptive tearm Strong gale
Wind speed (m/sec) 20.8 - 24.4
Wind speed (knots) 41 - 47


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.

09 - Strong gale

Beaufort number 10
Descriptive tearm Storm
Wind speed (m/sec) 24.5 - 28.4
Wind speed (knots) 48 - 55


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.

10 - Storm

Beaufort number 11
Descriptive tearm Violent storm
Wind speed (m/sec) 28.5 - 32.6
Wind speed (knots) 56 - 63


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.

11 - Violent storm

Beaufort number 12
Descriptive tearm Hurricane
Wind speed (m/sec) > 32.7
Wind speed (knots) > 64


The air is filled with foam and spray; sea completely white with driving spray; visibility is very seriously affected.


published on 2020/10/19 09:43:00 GMT+0 last modified 2020-12-18T10:07:29+00:00