The speed of sound in the atmosphere is most affected by variations in which of the following?

The speed of sound in the atmosphere is predominantly influenced by ambient temperature. As the temperature increases, air molecules move more rapidly, allowing sound waves to propagate faster. This relationship occurs because sound travels through air as vibrations of air molecules, and the energy imparted by higher temperatures increases the speed at which these molecules vibrate, thereby enhancing sound transmission.

While humidity levels can also affect the speed of sound, their impact is relatively smaller compared to that of temperature. Increased humidity means that there are more water vapor molecules in the air, which are lighter than dry air. This can increase the speed of sound slightly, but the primary driver remains the temperature of the air. Wind speed may affect the direction and perceived speed of sound but does not fundamentally alter the speed of sound itself through the medium. Finally, altitude affects temperature and pressure, which in turn can influence the speed of sound, but it is the ambient temperature at a given altitude that has the most direct and significant impact.