Beaufort
Wind Force 
|
Wind |
Criterion |
| Speed |
Descriptive term |
Sea |
Land |
| -Average- |
-Speed Range- |
American |
British |
State |
Description |
Wave Height |
| 0 |
0 |
<1kt
<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;
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.
Causes big patches foam blown to dense white streaks with wind's direction.
Whole sea surface has 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-medium ships may suffer view lost behind waves at times
Sea covered patches of long white foam,laying in the winds direction,
with wave crests edges 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. |
|
Knots to MPH
| kts |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
| 0 |
0 |
1 |
2 |
3 |
5 |
6 |
7 |
8 |
9 |
10 |
| 10 |
12 |
13 |
14 |
15 |
16 |
17 |
18 |
20 |
21 |
22 |
| 20 |
23 |
24 |
25 |
26 |
28 |
29 |
30 |
31 |
32 |
33 |
| 30 |
35 |
36 |
37 |
38 |
39 |
40 |
41 |
43 |
44 |
45 |
| 40 |
46 |
47 |
48 |
50 |
51 |
52 |
53 |
54 |
55 |
56 |
| 50 |
58 |
59 |
60 |
61 |
62 |
63 |
64 |
66 |
67 |
68 |
| 60 |
69 |
70 |
71 |
73 |
74 |
75 |
76 |
77 |
78 |
79 |
| 70 |
81 |
82 |
83 |
84 |
85 |
86 |
88 |
89 |
90 |
91 |
| 80 |
92 |
93 |
94 |
96 |
97 |
98 |
99 |
100 |
101 |
102 |
| 90 |
104 |
105 |
106 |
107 |
108 |
109 |
111 |
112 |
113 |
114 |
| 100 |
115 |
116 |
117 |
119 |
120 |
121 |
122 |
123 |
124 |
126 |
| 110 |
127 |
128 |
129 |
130 |
131 |
132 |
134 |
135 |
136 |
137 |
| 120 |
138 |
139 |
140 |
142 |
143 |
144 |
145 |
146 |
147 |
149 |
| 130 |
150 |
151 |
152 |
153 |
154 |
155 |
157 |
158 |
159 |
160 |
| 140 |
161 |
162 |
164 |
165 |
166 |
167 |
168 |
169 |
170 |
172 |
| 150 |
173 |
174 |
175 |
176 |
177 |
178 |
180 |
181 |
182 |
183 |
| 160 |
184 |
185 |
187 |
188 |
189 |
190 |
191 |
192 |
193 |
195 |
| 170 |
196 |
197 |
198 |
199 |
200 |
202 |
203 |
204 |
205 |
206 |
| 180 |
207 |
208 |
210 |
211 |
212 |
213 |
214 |
215 |
216 |
218 |
| 190 |
219 |
220 |
221 |
222 |
223 |
225 |
226 |
227 |
228 |
229 |
| kts |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
Conversion: 1 knot = 1.15 mph |
MPH to Knots
| mph |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
| 0 |
0 |
1 |
2 |
3 |
3 |
4 |
5 |
6 |
7 |
8 |
| 10 |
9 |
10 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
16 |
| 20 |
17 |
18 |
19 |
20 |
21 |
22 |
23 |
23 |
24 |
25 |
| 30 |
26 |
27 |
28 |
29 |
30 |
30 |
31 |
32 |
33 |
34 |
| 40 |
35 |
36 |
36 |
37 |
38 |
39 |
40 |
41 |
42 |
43 |
| 50 |
43 |
44 |
45 |
46 |
47 |
48 |
49 |
49 |
50 |
51 |
| 60 |
52 |
53 |
54 |
55 |
56 |
56 |
57 |
58 |
59 |
60 |
| 70 |
61 |
62 |
63 |
63 |
64 |
65 |
66 |
67 |
68 |
69 |
| 80 |
69 |
70 |
71 |
72 |
73 |
74 |
75 |
76 |
76 |
77 |
| 90 |
78 |
79 |
80 |
81 |
82 |
82 |
83 |
84 |
85 |
86 |
| 100 |
87 |
88 |
89 |
89 |
90 |
91 |
92 |
93 |
94 |
95 |
| 110 |
96 |
96 |
97 |
98 |
99 |
100 |
101 |
102 |
102 |
103 |
| 120 |
104 |
105 |
106 |
107 |
108 |
109 |
109 |
110 |
111 |
112 |
| 130 |
113 |
114 |
115 |
115 |
116 |
117 |
118 |
119 |
120 |
121 |
| 140 |
122 |
122 |
123 |
124 |
125 |
126 |
127 |
128 |
129 |
129 |
| 150 |
130 |
131 |
132 |
133 |
134 |
135 |
135 |
136 |
137 |
138 |
| 160 |
139 |
140 |
141 |
142 |
142 |
143 |
144 |
145 |
146 |
147 |
| 170 |
148 |
148 |
149 |
150 |
151 |
152 |
153 |
154 |
155 |
155 |
| 180 |
156 |
157 |
158 |
159 |
160 |
161 |
162 |
162 |
163 |
164 |
| 190 |
165 |
166 |
167 |
168 |
168 |
169 |
170 |
171 |
172 |
173 |
| mph |
0 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
Conversion: 1 mph = 0.868 kts |
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
95K nots = 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 MPH
|