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28 Beaufort scale
The Beaufort scale is an international scale of wind velocit-
ies from 0 (calm) to 12 (Hurricane force).
Beaufort number
Description
Speed
0
calm
< 1 km/h | < 1 mph
< 1 knots | < 0.3 m/s
1
light air
1.1-5.5 km/h | 1-3 mph
1-3 knots | 0.3-1.5 m/s
2
light breeze
5.6-11 km/h | 4-7 mph
1-3 knots | 0.3-1.5 m/s
3
gentle breeze
12-19 km/h | 8-12 mph
7-10 knots | 3.5-5.4 m/s
4
moderate breeze
20-28 km/h | 13-17 mph
11-16 knots | 5.5-7.9 m/s
5
fresh breeze
29-38 km/h | 18-24 mph
17-21 knots | 8.0-10.7 m/s
6
strong gale
39-49 km/h | 25-30 mph
22-27 knots | 10.8-13.8 m/
s
7
high wind
50-61 km/h | 31-38 mph
28-33 knots | 13.9-17.1 m/
s
8
gale
62-74 km/h | 39-46 mph
34-40 knots | 17.2-20.7 m/
s
9
strong gale
75-88 km/h | 47-54 mph
