Weather & Wind

Apparent Wind Calculator

Calculate the wind speed and angle experienced onboard from true wind and boat speed. It helps explain why the wind appears to move forward and strengthen as a sailing boat accelerates.

Angle convention: 0° is wind from directly ahead, 90° is from the beam and 180° is from directly astern.

i

True wind speed relative to the fixed Earth reference, before the boat's motion is included.

True wind speed relative to the fixed Earth reference, before the boat's motion is included.
i

Wind-from angle relative to the bow: ahead 0°, beam 90°, astern 180°.

°
Wind-from angle relative to the bow: ahead 0°, beam 90°, astern 180°.
i

Boat speed in the same horizontal reference used for the true wind.

Boat speed in the same horizontal reference used for the true wind.

Apparent wind

Apparent wind speed
11.7 kt
Apparent wind angle
59°

Measured from ahead using the wind-from convention.

Wind position
Forward of the beam
Forward component
6.0 kt
Side component
10.0 kt

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