When will the static air temperature equal ram air temperature?

The static air temperature will equal ram air temperature when the airplane is stationary. In this scenario, there is no airspeed causing an increase in temperature due to dynamic effects. Ram air temperature, which represents the temperature of the air as it moves toward the aircraft, is influenced by airspeed; when the aircraft is at rest, both temperatures align because the aircraft is not generating any ram pressure or temperature gradient.

For instance, while flying, especially at higher speeds or in maneuvering states, the ram air temperature typically rises above the static air temperature due to compressibility and friction effects. This difference highlights the nature of airflow around a moving aircraft. As such, the relevance of the aircraft's movement is crucial to understanding thermal effects in flight.