|
Beaufort
number |
Wind speed |
Description |
Wave height |
Sea
conditions |
Land
conditions |
Sea state
photo |
|
km/h |
mph |
kts |
m/s |
m |
ft |
|
0 |
<1 |
<1 |
<1 |
<0.3 |
Calm |
0 |
0 |
Flat. |
Calm.
Smoke rises vertically. |
 |
|
1 |
1-5 |
1-3 |
1-2 |
0.3-1.5 |
Light air |
0.1 |
0.33 |
Ripples
without crests. |
Wind
motion visible in smoke. |
 |
|
2 |
6-11 |
3-7 |
3-6 |
1.5-3.3 |
Light
breeze |
0.2 |
0.66 |
Small
wavelets. Crests of glassy appearance, not
breaking |
Wind felt
on exposed skin. Leaves rustle. |
 |
|
3 |
12-19 |
8-12 |
7-10 |
3.3-5.5 |
Gentle
breeze |
0.6 |
2 |
Large
wavelets. Crests begin to break; scattered
whitecaps |
Leaves
and smaller twigs in constant motion. |
 |
|
4 |
20-28 |
13-17 |
11-15 |
5.5-8.0 |
Moderate
breeze |
1 |
3.3 |
Small
waves. |
Dust and
loose paper raised. Small branches begin to
move. |
 |
|
5 |
29-38 |
18-24 |
16-20 |
8.0-10.8 |
Fresh
breeze |
2 |
6.6 |
Moderate
(1.2 m) longer waves. Some foam and spray. |
Branches
of a moderate size move. Small trees begin to
sway. |
 |
|
6 |
39-49 |
25-30 |
21-26 |
10.8-13.9 |
Strong
breeze |
3 |
9.9 |
Large
waves with foam crests and some spray. |
Large
branches in motion. Whistling heard in overhead
wires. Umbrella use becomes difficult. Empty
plastic garbage cans tip over. |