It is a radar device so the speed of sound is irrelevant. The speed of light in air (and hence the refractive index) does depend slightly on temperature / press

It is a radar device so the speed of sound is irrelevant. The speed of light in air (and hence the refractive index) does depend slightly on temperature / pressure, but not by very much: https://physics.stackexchange.com/questions/6872/refractive-index-of-air-in-dependence-of-temperature https://physics.stackexchange.com/questions/6872/refractive-...