How to determine at what distance from you was struck by lightning

So, expect the zipper with a stopwatch in hand. At the time of the flash, start the stopwatch when you hear the thunder, the stopwatch will be off. As a result, you will receive a time delay of the thunder – that is, the time during which the vibrations in the air passed from the place of discharge to you.

Further, the distance of the well-known formula is the product of speed of movement at the time. The time you have. As for the speed of sound in the atmosphere, for rough calculations it is sufficient to remember the value of 343 meters per second. If you want to calculate the distance more or less accurately, it should be remembered that in humid air the sound travels faster than in dry, and in hotter faster than the cold. For example, cold autumn when heavy rain the speed of sound in air is 338 m/sec, and hot and dry summers – 350 m/sec.

Now consider. For example, from lightning flashes to the sound of thunder it took 8 seconds.
Take the speed of sound is 343 m/s, then the distance to lightning will be 8 * 343 = 2744 meters, or (rounding) 2.7 kilometer. If the air temperature is 15 degrees Celsius at 80% humidity (rain average force), the speed of sound will be 341,2 m/sec, and the distance 2729,6 m (can be rounded to 2.73 km).

Can enter the tolerance on wind direction. If the wind is blowing in the direction of the zips towards you, the sound will pass this distance is somewhat faster, and the wind direction from you to the lightning – a bit slower. For rough calculations it is sufficient to remember that in the first case (wind lightning) distance should be decreased by 5%, while the second (wind and lightning) to increase by 5%. Thus, the delay of the thunder 8 seconds and speed of sound 343 m/s in the direction of the wind from the lightning to you the distance 2744 meters need to increase 137,2 m.