| Specifications
and equivalent speeds |
| Beaufort
wind scale |
Mean
Wind Speed |
Limits
of wind speed |
Wind
descriptive terms |
Probable
wave height in metres* |
Probable
maximum wave height in metres* |
Seastate |
Sea
descriptive terms |
| Knots |
m/s |
Knots |
m/s |
| 0 |
0 |
0 |
<1 |
0-0.2 |
Calm |
- |
- |
0 |
Calm (glassy) |
| 1 |
2 |
0.8 |
1-3 |
0.3-1.5 |
Light air |
0.1 |
0.1 |
1 |
Calm (rippled) |
| 2 |
5 |
2.4 |
4-6 |
1.6-3.3 |
Light breeze |
0.2 |
0.3 |
2 |
Smooth (wavelets) |
| 3 |
9 |
4.3 |
7-10 |
3.4-5.4 |
Gentle breeze |
0.6 |
1.0 |
3 |
Slight |
| 4 |
13 |
6.7 |
11-16 |
5.5-7.9 |
Moderate breeze |
1.0 |
1.5 |
3-4 |
Slight-Moderate |
| 5 |
19 |
9.3 |
17-21 |
8.0-10.7 |
Fresh breeze |
2.0 |
2.5 |
4 |
Moderate |
| 6 |
24 |
12.3 |
22-27 |
10.8-13.8 |
Strong breeze |
3.0 |
4.0 |
5 |
Rough |
| 7 |
30 |
15.5 |
28-33 |
13.9-17.1 |
Near gale |
4.0 |
5.5 |
5-6 |
Rough-Very rough |
| 8 |
37 |
18.9 |
34-40 |
17.2-20.7 |
Gale |
5.5 |
7.5 |
6-7 |
Very rough-High |
| 9 |
44 |
22.6 |
41-47 |
20.8-24.4 |
Severe gale |
7.0 |
10.0 |
7 |
High |
| 10 |
52 |
26.4 |
48-55 |
24.5-28.4 |
Storm |
9.0 |
12.5 |
8 |
Very High |
| 11 |
60 |
30.5 |
56-63 |
28.5-32.6 |
Violent storm |
11.5 |
16.0 |
8 |
Very High |
| 12 |
- |
- |
64+ |
32.7+ |
Hurricane |
14+ |
- |
9 |
Phenomenal |
| * |
- These values refer to well-developed wind waves of
the open sea.
- The lag effect between the wind getting up and the sea
increasing should be borne in mind.
|
|
