Definition
A counterclockwise change in wind direction over time, as observed in the Northern Hemisphere. For example, a wind shifting from north to west to south is backing. Backing winds with altitude often indicate the approach of a cold front or the presence of cold air advection.
Plain English
The wind is changing direction by rotating to the left (anti-clockwise) over time or with height. The opposite movement, rotating to the right, is called veering.
Context Anchor
Seen in weather briefings, forecasts, winds aloft information, and discussions of changing surface winds.
Derivation
From the older nautical and meteorological use of 'back,' meaning to move against the normal or expected direction. Sailors described a wind as 'backing' when it shifted opposite to the usual clockwise progression of weather systems in the Northern Hemisphere.
Why Pilots Care
Backing winds often signal an approaching warm front or other weather changes that affect turbulence, visibility, and flight planning.
Analogy
Think of a compass like a clock face. A backing wind moves the opposite way from the clock hands.
Intuition Check
Backing does not mean the wind is blowing backward. It means the direction the wind comes from is shifting counterclockwise on the compass.
Example Sentence 1
The forecast showed winds backing from the northwest to the southwest, suggesting a cold front was on its way.
Example Sentence 2
The pilot noted the wind backing during the preflight briefing and adjusted the crosswind landing plan.