The speed of sound in air depends on a number of factors - air temperature and pressure.  Generally the higher the altitude the lower the speed of sound.\n\nIn air, sound waves travel at around 330 metres/second (when the air temperature is 0 degrees centigrade). At 40 degrees centigrade (a very very hot day) the velocity increases to 354 metres/second in air.\n\nThe average figure for speed of sound at standard temperature and pressure is quoted as 343 metres per second or 767 miles per hour.
What is the seed of sound?