Sound bends like light because temperature changes its speed.

Evidence

Wind can also cause refraction effects because the velocity of sound within the medium is unaffected by the velocity of the medium. The velocity of a sound wave in a moving medium, when viewed from a fixed point, is the sum of the two velocities, so that it is increased when the sound is moving with the wind and is reduced when it is moving against the wind. As the velocity of air is generally less at ground level compared with the velocity higher up (due to the effect of the friction of the ground), sound waves are bent upward or downward depending on their direction relative to the wind. The degree of direction change depends on the rate of change in wind velocity as a function of height; a faster rate of change results in a greater direction change. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 340 (#qualifies, via linked claim)

Categorization

• XREF: connects to: Downwind sound is bent downward and waveguides along the ground, gaining intensity; Lower temperature slows the speed of sound predictably via thermal molecular motion; Sound speed in air varies only with the square root of absolute temperature — David Howard, Jamie Angus, coustics and Psychoacoustics, 65 (+4 more)

Broader Connections

• Air’s speed of sound varies only with the square root of absolute temperature. #expands (0.90)
• Wind bends sound waves because air velocity changes with height #qualifies (0.85) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 340
• Temperature refraction makes distant concertgoers hear more noise than nearby ones #exemplifies (0.85)
• Atmospheric physics creates striking asymmetries in how sound travels #expands (0.80)