Which factor does not affect density altitude?

Density altitude is a concept that defines how high an aircraft feels it is operating based on the density of the air. It is influenced by several atmospheric factors, which include temperature, humidity, and air pressure.

Temperature plays a crucial role; as temperature increases, air density decreases, which in turn increases density altitude. Similarly, humidity affects air density; higher humidity means more water vapor in the air, which is less dense than oxygen and nitrogen, leading to a higher density altitude. Altitude itself is also a critical factor since the density of air decreases with increased elevation, affecting the performance of aircraft.

Wind velocity, on the other hand, does not have a direct impact on density altitude. While wind can affect flying conditions and performance, it does not change the density of the air at a given altitude. Therefore, of the factors listed, wind velocity is the one that does not influence density altitude.