A gust is followed by a lull (or slackening) in the wind speed.[2] The wind is measured using an anemometer or estimated with a windsock.Any significant variation at this mean wind during the ten minutes preceding the observation are noted as gusts in messages such as METAR.[1][4] In marine meteorology, the top speed of a burst is expressed in meters per second (m/s) or in knots, while the Beaufort scale is used for reporting the mean speed.When the maximum speed exceeds the average speed by 10 to 15 knots (19 to 28 km/h; 12 to 17 mph), the term gusts is used while strong gusts is used for departure of 15 to 25 knots (28 to 46 km/h; 17 to 29 mph), and violent gusts when it exceeds 25 knots (46 km/h; 29 mph).
