How Far Away is Lightning From Me?

To estimate the distance between you and a lightning flash, use the "Flash to Bang" method: If you observe lightning, count the number of seconds until you hear thunder. Divide the number of seconds by five (5) to get the distance (in miles) the lightning is away from you.


If you see lightning and it takes 10 seconds before you hear the thunder, then the lightning is 2 miles away from you (10 divided by 5 = 2 miles).

If Thunder is heard The Lightning is...
5 seconds after a Flash
1 mile away
10 seconds after a Flash
2 miles away
15 seconds after a Flash
3 miles away
20 seconds after a Flash
4 miles away
25 seconds after a Flash
5 miles away
30 seconds after a Flash
6 miles away
35 seconds after a Flash
7 miles away
40 seconds after a Flash
8 miles away

It is recommended that you should be in a safe location if the time between the lightning flash and the rumble of thunder is 30 seconds or less.


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Go to Outdoor Lightning Safety - When a Safe Location is Nearby

Go to Outdoor Lightning Safety - When a Safe Location is NOT Nearby

Go to Lightning Safety Outdoors is the U.S. government's official web portal to all federal, state and local government web resources and services.