Free Wind Speed Conversion calculator with clear step-by-step results.
Converts between the four units wind is quoted in and extrapolates to a different height using the logarithmic wind profile, since wind speed rises with height above ground at a rate governed by surface roughness. The Beaufort force gives a descriptive scale for the measured speed.
Log wind profile
v(z2) = v(z1) x ln(z2 / z0) / ln(z1 / z0)
Beaufort force
Force = round((speed m/s / 0.836)^(2/3))
About 0.0002 m over open water, 0.03 over open farmland, 0.1-0.3 with hedges and scattered buildings, and 0.5-1.5 in suburbs and forest.
Wind shear is substantial - at 0.03 m roughness, speed at 50 m is roughly 25% higher than at 10 m, and wind power scales with the cube of speed.