US Sailing Level 1 LSR Practice Exam

Apparent wind is the wind direction and speed as measured by a moving weather station. It’s the wind you actually feel and read on a boat or any moving platform, because it combines the true wind in the environment with the wind generated by your own motion. In sailing, sails respond to the apparent wind, not the wind relative to the ground, so this measurement is what matters for trim and navigation. If there’s no true wind, moving yourself forward still creates an apparent wind from ahead—the faster you go, the stronger the apparent wind you experience. True wind, by contrast, is what a stationary observer would measure, after accounting for the observer’s movement. Ground wind and local wind aren’t standard terms for this measurement.