Wind Factors

Beaufort Wind Scale

Wind SpeedWMO*
Effects observed on landEffects observed on the sea
0under 1under 1



CalmSea is like a mirror
11 - 31 - 31Light airRipples with appearance of scales; no foam crests
24 - 64 - 72-3Light breezeSmall wavelets; crests of glassy appearance, not breaking
37 - 108 - 124-5Gentle breezeLarge wavelets; crests begin to break; scattered whitecaps
411-1613-186-8Moderate breezeSmall waves, becoming longer; numerous whitecaps
517-2119-249-11Fresh breezeModerate waves, taking longer form; many whitecaps; some spray
622-2725-3112-14Strong breezeLarger waves forming; whitecaps everywhere; more spray
728-3332-3815-17Near galeSea heaps up; white foam from breaking waves begins to be blown in streaks
834-4039-4618-20GaleModerately high waves of greater length; edges of crests begin to break into spindrift; foam is blown in well-marked streaks
941-4747-5421-24Strong galeHigh waves; sea begins to roll; dense streaks of foam; spray may begin to reduce visibility
1048-5555-6325-28StormVery high waves with overhanging crests; sea takes white appearance as foam is blown in very dense streaks; rolling is heavy and visibility is reduced
1156-6364-7229-32Violent stormExceptionally high waves; sea covered with white foam patches; visibility further reduced
1264 and over73 and over33 and overHurricaneAir filled with foam; sea completely white with driving spray; visibility greatly reduced
* World Meteorological Organization

Devised by British Rear-Admiral, Sir Francis Beaufort in 1805
based on observations of the effects of the wind


Typical Turbine Loudness vs. Wind Speed Chart



Curve for Turbines Recommended by UPC Wind

Operating at Beaufort Wind Scale of 3-9