Wind gust 10 to 15 knots, the term "gusts" is used while "strong gusts" is used for departure of 15 to 25 knots, and "violent gusts" when it exceeds 25 knots. Wind gust A gust or wind gust is a brief increase in the speed of the wind, usually less than 20 seconds. It is of a more transient character than a squall, which last minutes, and is followed by a lull or slackening in the wind speed. Generally, winds are least gusty over large water surfaces and most gusty over rough land and near high buildings. The wind is measured using
USA 17 velocity made good was about , or about 1.8 times wind speed. "USA 17" took 63 minutes to reach the downwind mark, so her velocity made good downwind was about , or about 2.5 times wind speed. The measured wind velocity is taken at near sea level, and does not account for effects of wind gradient with reported true wind speed of at mast head height of over . The measured sea-level wind direction shifted away from 180 degrees between the time of setting of the course and commencement of sailing of the downwind leg, by which time wind direction