Conversion table for knots to miles per hour, kilometers per hour, Beaufort Wind Scale, 
KTS to MPH
5
Knots
=
5.8
MPH
10
Knots
=
11.5
MPH
15
Knots
=
17.3
MPH
20
Knots
=
23.0
MPH
25
Knots
=
28.8
MPH
30
Knots
=
34.6
MPH
35
Knots
=
40.3
MPH
40
Knots
=
46.1
MPH
45
Knots
=
51.8
MPH
50
Knots
=
57.6
MPH
55
Knots
=
63.4
MPH
60
Knots
=
69.1
MPH
65
Knots
=
74.9
MPH
70
Knots
=
80.6
MPH
75
Knots
=
86.4
MPH
80
Knots
=
92.2
MPH
85
Knots
=
97.9
MPH
90
Knots
=
103.7
MPH
95
Knots
=
109.4
MPH
100
Knots
=
115.2
MPH
105
Knots
=
121.0
MPH
110
Knots
=
126.7
MPH
115
Knots
=
132.5
MPH
120
Knots
=
138.2
MPH
125
Knots
=
144.0
MPH
130
Knots
=
149.8
MPH
135
Knots
=
155.5
MPH
140
Knots
=
161.3
MPH
145
Knots
=
167.0
MPH
150
Knots
=
172.8
MP
KTS to KPH
5 Knots = 9.3 KPH
10 Knots = 18.5 KPH
15 Knots = 27.8 KPH
20 Knots = 37.0 KPH
25 Knots = 46.3 KPH
30 Knots = 55.6 KPH
35 Knots = 64.8 KPH
40 Knots = 74.1 KPH
45 Knots = 83.3 KPH
50 Knots = 92.6 KPH
55 Knots = 101.9 KPH
60 Knots = 111.1 KPH
65 Knots = 120.4 KPH
70 Knots = 129.6 KPH
75 Knots = 138.9 KPH
80 Knots = 148.2 KPH
85 Knots = 157.4 KPH
90 Knots = 166.7 KPH
95 Knots = 175.9 KPH
100 Knots = 185.2 KPH
105 Knots = 194.5 KPH
110 Knots = 203.7 KPH
115 Knots = 213.0 KPH
120 Knots = 222.2 KPH
125 Knots = 231.5 KPH
130 Knots = 240.8 KPH
135 Knots = 250.0 KPH
140 Knots = 259.3 KPH
145 Knots = 268.5 KPH
150 Knots = 277.8 KPH
Beaufort Wind Scale
Beaufort Wind Force Wind Criterion
Speed Descriptive term Sea Land
Average Range American British State Description Wave Height
0 0 <1 kt
<1 mph
<1 km/h
Light Calm Calm Sea like a mirror. 0 Smoke rises vertically.
1 2 kt
2 mph
3 km/h
1-3 kts
1-3 mph
1-5 km/h
Light Light air Smooth Ripples with the appearance of scales are formed, but without foam crests. ¼ ft
0.1 m
Direction shown by smoke but not by wind vanes.
2 5 kts
6 mph
9 km/h
4-6 kts
4-7 mph
6-11 km/h
Light Light breeze Smooth Small wavelets, still short but more pronounced, crests have a glassy appearance and do not break. ½-1 ft
0.2 m
Wind felt on face; leaves rustle; ordinary vane moved by wind.
3 9 kts
10 mph
16 km/h
7-10 kts
8-12 mph
12-19 km/h
Gentle Gentle breeze Slight Large wavelets. Crests begin to break. Foam of glassy appearance. 2-3 ft
0.6 m
Leaves and small twigs in constant motion; wind extends light flag.
4 13 kts
16 mph
24 km/h
11-16 kts
13-18 mph
20-28 km/h
Moderate Moderate breeze Moderate Small waves, becoming longer. 3½-5 ft
1 m
Raises dust and loose paper; small branches are moved.
5 19 kts
22 mph
34 km/h
17-21 kts
19-24 mph
29-38 km/h
Fresh Fresh breeze Rough Moderate waves, taking a more pronounced long form. (Chance of some spray). 6-8 ft
2 m
Small trees in leaf begin to sway.
6 24 kts
28 mph
44 km/h
22-27 kts
25-31 mph
39-49 km/h
Strong Strong breeze Very Rough Large waves begin to form; the white foam crests are more extensive everywhere. (Probably some spray). 9½-13 ft
3 m
Large branches in motion; umbrellas used with difficulty.
7 30 kts
35 mph
56 km/h
28-33 kts
32-38 mph
50-61 km/h
Strong Near gale High Sea heaps up and white foam from breaking waves begins to be blown in streaks along the direction of the wind. 13½-19 ft
4 m
Whole trees in motion; inconvenience felt when walking against the wind.
8 37 kts
43 mph
68 km/h
34-40 kts
39-46 mph
62-74 km/h
Gale Gale Very High Moderately high waves of greater length; edges of crests begin to break into spondrift. The foam is blown in well marked streaks along the direction of the wind. 18-28 ft
5.5 m
Breaks twigs off trees; generally impedes progress
9 44 kts
51 mph
82 km/h
41-47 kts
47-54 mph
75-88 km/h
Gale Strong Gale Very High High waves. Dense streaks of foam along the direction of the wind. Crests of waves begin to topple, tumble and roll over. Spray may affect visibility. 23-32 ft
7 m
Slight structural damage; chimney-pots and slates removed.
10 52 kts
59 mph
96 km/h
48-55 kts
55-63 mph
89-102 km/h
Whole Gale Storm Phenomenal Very high waves with long overhanging crests. The resulting foam in great patches is blown in dense white streaks along the direction of the wind. On the whole the surface of the sea takes a white appearance. Visibility affected. 29-41 ft
9 m
Trees uprooted; considerable structural damage.
11 60 kts
68 mph
110 km/h
56-63 kts
64-72 mph
103-117 km/h
Whole Gale Violent Strom Phenomenal Exceptionally high waves. (Small and medium sized ships might be for a time lost to view behind the waves.) The sea is completely covered with long white patches of foam lying along the direction of the wind. Everywhere the edges of the wave crests are blown into froth. Visibility affected. 39-46 ft
11.5 m
Widespread damage; very rarely experienced.
12 68 kts
78 mph
124 km/h
64-71 kts
72-82 mph
118-132 km/h
Hurricane n/a n/a The air is filled with foam and spray. Sea completely white with driving spray; visibility very seriously affected. >52 ft
>14 m
Countryside is devastated.



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