Classification of Wind Speeds

Beaufort number	Wind speed (km/hr)	International description	US Weather Bureau description	Effect of wind on the Sea
0	<1	Calm	Light Wind	Small wavelets
1	1-5	Light Air	Light Wind	Small wavelets
2	6-11	Light Breeze	Light Wind	Small wavelets
3	12-19	Gentle Breeze	Gentle-moderate	Large wavelets to small waves
4	20-28	Moderate Breeze	Gentle-moderate	Large wavelets to small waves
5	29-38	Fresh Breeze	Fresh wind	Moderate waves, many whitecaps
6	39-49	Strong gale	Strong wind	Large waves, many whitecaps
7	50-61	Fresh Breeze	Strong wind	Large waves, many whitecaps
8	62-74	Fresh gale	Gale	High waves, foam streaks
9	75-88	Stong gale	Gale	High waves, foam streaks
10	89-102	Whole gale	Whole gale	Very high waves, rolling sea
11	103-117	Storm	Whole gale	Very high waves, rolling sea
12-17	>117	Hurricane	Hurricane	Sea white with spray and foam

Last modified June 25, 2008 by Vanessa Pearce.
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