12.3. Beaufort Scale of Wind Force
Beaufort
Scale
Description Average
Wind Force in
m/s
Average
Wind force
in kn
Description in
the Weather
Chart
0 calm <0.2 <1
1
light air
0.3 – 1.5
1 – 3
2
slight breeze
1.6 – 3.3
4 –6
3
gentle breeze
3.4 – 5.4
7 – 10
4 moderate
breeze
5.5 – 7.9
11 – 15
5
fresh breeze
8.0 – 10.7
16 – 21
6
strong breeze
10.8 – 13.8
22 – 27
7
moderate gale 13.9 – 17.1
28 – 33
8
fresh gale
17.2 – 20.7
34 – 40
9
strong gale
20.8 – 24.4
41 – 47
10
whole gale
24.5 – 28.4
48 – 55
11
storm
28.5 – 32.6
56 – 63
12 hurricane
>32.6 >63
