Can you tell how close a storm is by the thunder?

Answer 1

Roughly. Count the seconds between the time you see the lightning and the time you hear the thunder. Since sound travels slower than light, the thunder LAGS the lightning more the farther it travels. The speed of light is so high that it's OK to assume that it reaches you in no time. So the lag between the lightning and the thunder is just the time it takes for the sound to reach you. On paper, all you'd need to know is the speed of sound. Unfortunately, it varies quite a bit depending on atmospheric conditions ... particularly temperature ... and is especially variable around thunderstorms. PLUS -- in the unstable, nonhomogeneous atmosphere around thunderstorms, the sound most likely travels a curved path to you, which is a bit longer than if it traveled straight. But let's ignore all of that, and use the time-lag of the thunder to roughly calculate how far away from you the lightning strike was. With the air temperature in the mid-70's, the speed of sound is about 1125 ft (343 m) per second. If you accurately count the seconds between the appearance of the lightning and the beginning of the sound of thunder, you can translate that number roughly into 1 mile of distance for every 4.7 seconds, or 1 kilometer of distance for every 2.9 seconds.

Answer 2

Yes, you can estimate how close a storm is by counting the seconds between the lightning flash and the sound of thunder. Each second is roughly equivalent to 1,100 feet (330 meters), so dividing the seconds by 5 will give you the distance in miles. If you hear thunder immediately after seeing lightning, the storm is very close.