| Beaufort number | Wind speed |
The mean wind speed (knob / km/h / mph) |
Description | Wave height | Sea conditions | Country conditions | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| kt | km/h | mph | m/s | m | ft | |||||
| 0 |
0 |
0 |
0 |
0-0.2 |
0 / 0 / 0 |
Quiet |
0 |
0 |
Glassy. |
Smoke rises vertically . |
| 1 |
1-3 |
1-6 |
1-3 |
0.3-1.5 |
2 / 4 / 2 |
Air regulation |
0.1 |
0.33 |
Curling without foampeaks. |
Weak movement in smoke in the wind direction. |
| 2 |
4-6 |
7-11 |
4-7 |
1.6-3.3 |
5 / 9 / 6 |
Weak winds |
0.2 |
0.66 |
Short waves are not broken. |
Movement in small leaf. |
| 3 |
7-10 |
12-19 |
8-12 |
3.4-5.4 |
9 / 17 / 11 |
Light wind |
0.6 |
2 |
Short waves break. |
Leaf and twigs move pennants lifted. |
| 4 |
11-16 |
20-29 |
13-18 |
5.5-7.9 |
13 / 24 / 15 |
Smooth wind |
1 |
3.3 |
Small waves of foampeaks. |
Dust and paper lifted twigs and small branches move. |
| 5 |
17-21 |
30-39 |
19-24 |
8.0-10.7 |
19 / 35 / 22 |
Fresh wind |
2 |
6.6 |
Moderate (1.2 m) long waves. Foampeaks and a foamspray . |
Small trees are moving. |
| 6 |
22-27 |
40-50 |
25-31 |
10.8-13.8 |
24 / 44 / 27 |
Hard wind |
3 |
9.9 |
Large waves of foampeaks everywhere. |
Movement of large branches. Airwires sing. It is difficult to use the umbrella. |
| 7 |
28-33 |
51-62 |
32-38 |
13.9-17.1 |
30 / 56 / 35 |
Rigid wind |
4 |
13.1 |
Big waves break up and foam kept in stripes in the wind direction. |
Large trees are moving. Difficult to go against the wind. |
| 8 |
34-40 |
63-75 |
39-46 |
17.2-20.7 |
37 / 68 / 42 |
Hard breeze |
5.5 |
18 |
Moderate high waves where the wavebreak broken for foamspray which is being held in stripes in the wind direction. |
Tvig and break branches of trees. Cars are difficult to keep on the road. |
| 9 |
41-47 |
76-87 |
47-54 |
20.8-24.4 |
44 / 81 / 50 |
Stormy breeze |
7 |
23 |
High waves (2.75 m) which overturns with massive foamspray. |
Major branches of the trees breaking. Roofstone blowing down. |
| 10 |
48-55 |
88-102 |
55-63 |
24.5-28.4 |
52 / 96 / 60 |
Storm |
9 |
29.5 |
Very high waves. Almost white surface. visibility deteriorated because of strong foamspray. |
Trees torn up with the fumble. Major damage to buildings . |
| 11 |
56-63 |
103-117 |
64-72 |
28.5-32.6 |
60 / 111 / 69 |
Strong storm |
11.5 |
37.7 |
Uncommon high waves. visibility very degraded because of strong foamspray. |
Numerous damage to buildings and airwires. |
| 12 |
>63 |
>117 |
>72 |
>32.7 |
N/A |
Hurricane |
14+ |
46+ |
Enormous waves. The air filled with foam to deteriorate term effect. |
Massive and extensive damage to buildings and everything upright. |
