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

Movie about the Beaufort Scale of Wind Speeds

Last modified January 8, 2010 by Randy Russell.

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