# Why Does Sound Travel Faster in Warm Air?

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## How the Speed of Sound Changes with Temperature

• Sound travels faster at higher temperatures. The formula for figuring out the speed of sound is
v = 331 m/s + 0.6m/s/degree

where v is velocity, m is meters, s is seconds and degree is degrees Celsius.
This formula is accurate at typical humidity.

So, at 0 degrees Celsius (freezing) sound would travel at 331 m/s, and on a very hot day (40 degrees Celsius) it would travel at 331 + 0.6*40 = 355 m.s.

## Why the Speed of Sound Changes with Temperature

• Temperature is a measure of heat. At higher temperatures, molecules are more energetic and can vibrate faster, thus, sound waves can travel faster through warmer air.

## How does Humidity Affect the Speed of Sound?

• According to Sengpiel audio, the speed of sound is also slightly affected by humidity. At 20 degrees Celsius, the speed of sound at 0 percent humidity is 343.4 m/s, at 50 percent humidity it is 344.0 m/s and at 100% humidity it is 344.6 m/s.

## What is the Fastest Speed of Sound in Air?

• The hottest recorded temperature on Earth is 53 degrees Celsius. At that temperature, sound would travel at 368 m/s.

## What is the Slowest Speed of Sound in Air?

• The coldest recorded temperature on Earth is -89 degrees Celsius. At that temperature, sound would travel at 278 m/s.