What format is used to express wind direction in aviation?

Wind direction in aviation is expressed as a three-digit number followed by the wind speed in knots. The three-digit number represents the wind's direction in degrees, measured clockwise from true north. For instance, a wind blowing from the northeast at 30 knots would be expressed as "045/30," indicating a wind direction of 045 degrees and a speed of 30 knots. This format is standardized and is crucial for accurately conveying weather information to pilots for safe navigation and operation of aircraft.

Using just degrees true without speed, as would be suggested in another option, would not provide a complete picture of the wind's impact on flight. Additionally, representing wind direction as a four-digit number or a single letter would not conform to the standardized measures utilized in aviation meteorology.