Calculating the Distance to Lightning Strikes
By Chad Upton | Editor
I love watching electrical storms. The time between strikes builds anticipation; the light show is epic and the sound is awe inspiring.
As a kid, I heard that if you count the seconds between the sight of the lightning and the sound of the thunder, the distance to the strike is one mile for every second you count. It’s a simple model, but it’s far from accurate.
It’s actually closer to 5 seconds for every mile.
For those who don’t know, you see the lightning before you hear the thunder because light travels much faster than sound, about 200,000 km per second faster (186,282 miles per second).
Depending on the environment, sound travels at about 350 meters per second (1150 feet per second). To calculate the distance, you can multiply the number of seconds by the speed of sound in your preferred units above.
If you count 10 seconds between the lightning and the thunder, the strike was about 3.5 km (2.17 miles away). To make it easier, use this lightning distance calculator.
Thanks to Kristen for this suggestion.
Image: John Fowler (cc)