Gust Factor

The gust factor is the ratio between the peak wind gust speed and the mean (sustained) wind speed over a given period. A gust factor of 1.5 means gusts are 50% stronger than the sustained wind. Understanding gust factors is essential for approach planning, crosswind assessment, and turbulence avoidance.

In METAR reports, gusts are reported when the peak instantaneous wind speed exceeds the mean wind speed by 10 knots or more — for example, 27015G25KT indicates wind from 270° at 15 knots gusting to 25 knots (gust factor of 1.67).

Pilots add a gust correction to their approach speed — typically half the gust increment added to the normal reference speed (Vref). In the example above, the gust increment is 10 knots, so the pilot would add 5 knots to Vref. Some operators use the full gust increment as an additive.