How can I stay a safe distance from lightning?

While lightning has been recorded to strike at a distance of 10 miles, the rule of thumb used for safety is a six mile distance. Thus, seeking shelter is recommended if the lightning is six miles away or less.

There are a number of lightning detectors on the market using various methods to determine lightning distance. However, an effective and free method is known as the flash-to-bang method. It takes five seconds for thunder to travel one mile. Thus, when you see the flash of lightning, you should begin counting the seconds until you hear the bang of thunder. Dividing that number by five will give you the distance in miles. If you are able to count 30 seconds or less, it means that the lightning is six miles away or less. Of course a more conservative method would be to seek shelter at the first sight of lightning or the first sound of thunder, regardless of the distance.
(This answer provided for NATA by the Marist College Athletic Training Education Program.)