A gust is a sudden increase in wind speed, often with a change in direction lasting less than one minute and it is a local effect. A gust will only be reported or forecast if 10 kt or more above the mean wind speed.
A lull is a sudden decrease in wind speed.
A squall is a sudden increase in wind speed, often with a change in direction. Lasting for one minute or more and can cover a wide area. It is often associated with cumulonimbus cloud and cold fronts.
A gale exists when the sustained wind speed exceeds 33 kt, or gusts exceed 42 kt.
A hurricane-force wind exists when sustained wind speed exceeds 63 kt.