Prevailing Wind

The wind direction occurring most frequently at a location during a stated period or season.

A prevailing direction is a statistical description derived from observations and is often shown by a wind rose. It may change by season, time of day, weather pattern or height above the surface, and the most frequent direction need not account for a majority of all observations.

Local coastline, terrain, sea breezes and frontal systems can produce winds very different from the climatological prevailing direction on a particular day. Passage and harbour decisions therefore require current forecasts and observations rather than the prevailing wind alone.