Beaufort Wind Scale

There is one scale for land and one for maritime. It was created by Rear Admiral Sir Francis Beaufort (1774-1857). In 1955, The U.S. Weather Bureau added forces 13 to 17 to indicate higher wind strengths as in tropical storms, but their usage has been limited.

Force Descriptionknotskm/hmph
  1. calm
  2. light air
  3. light breeze
  4. gentle breeze
  5. moderate breeze
  6. fresh breeze
  7. strong breeze
  8. near gale (strong wind)
  9. gale
  10. strong gale
  11. storm
  12. violent storm
  13. hurricane
 <1
1-3
4-6
7-10
11-16
17-21
22-27
28-33
34-40
41-47
48-55
56-63
64+		 <1
1-5
6-11
12-19
20-29
30-39
40-50
51-61
62-74
75-87
88-101
102-117
118+		 <1
1-3
4-7
8-12
13-18
19-24
25-31
32-38
39-46
47-54
55-63
 64-73
74+