22
Beaufort Scale Description Wind Speed Land Condition
0 Calm
< 1 km/h
Calm. Smoke rises vertically.
< 1 mph
< 1 knots
< 0.3 m/s
1 Light air
1.1 ~ 5km/h
Smoke drift indicates wind direction.
Leaves and wind vanes are stationary.
1 ~ 3 mph
1 ~ 3 knots
0.3 ~ 1.5 m/s
2 Light breeze
6 ~ 11 km/h
Wind felt on exposed skin. Leaves rustle.
Wind vanes begin to move.
4 ~ 7 mph
4 ~ 6 knots
1.6 ~ 3.3 m/s
3 Gentle breeze
12 ~ 19 km/h
Leaves and small twigs constantly moving,
light ags extended.
8 ~ 12 mph
7 ~ 10 knots
3.4 ~ 5.4 m/s
4
Moderate
breeze
20 ~ 28 km/h
Dust and loose paper raised. Small
branches begin to move.
13 ~ 17 mph
11 ~ 16 knots
5.5 ~ 7.9 m/s
5 Fresh breeze
29 ~ 38 km/h
Branches of a moderate size move.
Small trees in leaf begin to sway.
18 ~ 24 mph
17 ~ 21 knots
8.0 ~ 10.7 m/s
6 Strong breeze
39 ~ 49 km/h
Large branches in motion. Whistling heard
in overhead wires. Umbrella use becomes
difcult. Empty plastic bins tip over.
25 ~ 30 mph
22 ~ 27 knots
10.8 ~ 13.8 m/s
7 High wind
50 ~ 61 km/h
Whole trees in motion. Effort needed to
walk against the wind.
31 ~ 38 mph
28 ~ 33 knots
13.9 ~ 17.1 m/s
8 Gale
62 ~ 74 km/h
Some twigs broken from trees.
Cars veer on road. Progress on foot is
seriously impeded
39 ~ 46 mph
34 ~ 40 knots
17.2 ~ 20.7 m/s
9 Strong gale
75 ~ 88 km/h
Some branches break off trees, and some
small trees blow over. Construction /
temporary signs and barricades blow over.
47 ~ 54 mph
41 ~ 47 knots
20.8 ~ 24.4 m/s
10 Storm
89 ~ 102 km/h
Trees are broken off or uprooted,
structural damage likely.
55 ~ 63 mph
48 ~ 55 knots
24.5 ~ 28.4 m/s
11 Violent storm
103 ~ 117 km/h
Widespread vegetation and structural
damage likely.
64 ~ 73 mph
56 ~ 63 knots
28.5 ~ 32.6 m/s
12 Hurricane force
≥ 118 km/h
Severe widespread damage to vegetation
and structures. Debris and unsecured
objects are hurled about.
≥ 74 mph
≥ 64 knots
≥ 32.7m/s
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