I forgot, how do count how many miles away a thunderstorm is?

Answer 1

1 mile for every 5-7 seconds after lightning the thunder is heard

Answer 2

You need two things: light and sound. A lightning strike provides both (a flash, followed by thunder).

Light travels so fast that the flash of a lightning strike reaches your eyes essentially instantaneously. However, the thunder produced by the strike travels about 761 miles per hour. This means that in 1 second, sound travels approximately 1/5 of a mile.

So, if you see a lightning strike, then hear the thunder 5 seconds later, the lightning was about 1 mile away. 10 seconds means 2 miles, 15 seconds means three miles.

Answer 3

Count the number of second between when you first see a lightning flash and when you hear the thunder, then divide the number by 5