How To Estimate Your Distance From Lightning

A cool trick to measure the distance of lightning from your location is to start counting like, "one one thousand," "two one thousand," "three one thousand," etc... when you see a flash of lightning. Then when you hear thunder stop counting and divide your count by five. This gives you the approximate distance in miles between you and the lightning strike.

During a thunder storm it is a fun game to do this for each flash. Then based on the differences in distance between each strike you can tell if the lightning is moving away from you or towards you.

The mathematical approximation comes from the difference between the speed of light, the lightning flash, and the slower speed of sound, the rumbling thunder.