We all do it: Counting the delay between seeing the lightning and hearing the thunderclap (seeing the light is almost instantaneous, but sound only travels at 700 miles per hour) The gap in five-second chunks amounts to the bolt being a mile away. If you get to ten seconds, it’s two miles, you’re probably thinking you’re safe.
BUT
You can hear thunder up to 25 miles away, that would be quite a big delay, nevertheless, lightning from the centre of the storm can traverse a distance of, you guessed it, 25 miles. So, even if you count to 125 seconds, you could still be hit. Safest place to be is in a Faraday cage…most of us have one, they’re called cars. A building is relatively safe too. Although think on, the Empire State Building gets struck by lightning around 25 times a year.
More information about lightning storms here.