Wind direction is considered variable when:

Wind direction is considered variable when the direction fluctuates by 60° or more. This threshold is significant because it indicates considerable instability in the wind's directional flow, which can affect aviation operations and weather forecasting. When wind direction changes substantially, pilots and meteorologists need to be aware of these fluctuations as they can lead to shifts in weather patterns and influence aircraft performance, including takeoffs and landings.

Options that suggest other criteria for wind direction variability, such as speed or smaller degrees of change, do not adequately capture the level of fluctuation that signifies a truly variable wind situation. Variable winds typically denote a lack of a steady direction, which is critical for safe and effective navigation and operational planning in aviation.