Definition
The wind direction that occurs most often at a given location over time. At an airport, the prevailing winds determine the orientation of the primary runway, since aircraft take off and land most efficiently and safely when pointed into the wind.
Plain English
The direction the wind usually blows from at a particular place. Airports are designed around this so that the main runway lines up with the wind that shows up most days.
Context Anchor
Seen in runway layout, runway numbering, and airport planning discussions, especially when explaining why a runway points in a certain direction.
Derivation
Prevailing' comes from the Latin 'praevalere,' meaning 'to be stronger' or 'to have the upper hand.' The prevailing winds are the ones that 'win out' most of the time at that location.
Why Pilots Care
Runways are aligned with prevailing winds so most takeoffs and landings can be made into the wind, improving control and performance.
Intuition Check
Do not read prevailing winds as the wind happening right now. Prevailing winds means the usual wind pattern for that place over time.
Example Sentence 1
The airport's primary runway runs east-west because the prevailing winds in that region come from the west.
Example Sentence 2
Pilots review prevailing wind data when planning cross-country flights to anticipate typical en route conditions.