Plain English Meaning

Downwind means going the same way the wind is going. If the wind is blowing from north to south, then south is downwind.

Full Definition

The direction toward which the wind is blowing; movement or position in the same direction the wind is travelling. In flight, an aircraft is downwind when the wind is pushing it from behind, increasing its groundspeed and carrying it away from the wind's source.

Context Anchor

Seen when discussing wind correction, ground track, and how wind affects an airplane during straight-and-level flight.

Derivation

From Old English 'dun' (down) and 'wind.' 'Down' here doesn't mean lower in altitude — it means 'in the direction of flow,' the same way water flows 'downstream.' Downwind is simply the direction the wind is flowing toward.

Why Pilots Care

Higher groundspeed shortens the for - and changes the amount of needed compared with flight.