Calculate the distance from lightning in feet or meters. Sound travels at a speed of about 344 meters, or 1,129 feet, per second. To calculate your distance from the lightning in meters, just round 344 down to 340 and multiply the number of seconds by 340. read more
The National Weather Service recommends taking cover if the time between the lightning flash and the rumble of thunder is 30 seconds or less, which indicates the lightning is about 6 miles away or closer. read more