Question

Why does the sound travel faster on a cloudy day than on a dry day?

Answer 1

The velocity of sound:

The velocity of sound in air ($V$) can be given by the formula as shown-

$V=\sqrt{\raisebox{1ex}{$\gamma P$}\!\left/ \!\raisebox{-1ex}{$\rho $}\right.}$

Here, $\gamma$ represents the ratio of specific heats, which is equal to 1.4 for air.

$P$ represent the pressure of the air.

$\rho$ represent the density of the air.

1. Effect of humidity-as the humidity of air increases the density $\rho$ of air decreases. Hence speed of sound increases and as the humidity of air decrease its density increase which decreases the velocity of sound.
2. During cloudy days the humidity of air increase and hence the density of air decrease, so the velocity of sound also increase and $\rho$decrease.

Hence, on cloudy days the sound travels faster.