Fun Facts

Heat Lightning: A Myth

A hot summer night is the only time of the year you will see heat lightning. It is a misconception that you need the heat and humidity to produce the lightning. The truth is, heat lightning does not actually exist. The flashes of light are indeed lightning but the thunderstorm is far away from you so the sound of thunder or the rain do not travel to your location. The speed of light is much faster then the speed of sound which is how this process occurs. You can see lightning from a storm up to 100 miles away but you can only hear the thunder from a storm that is within 10-15 miles range. The sound of thunder is refracted and reflected through the atmosphere, and the speed is affected by the temperature/density of the air and the curvature of the earth (B. Donegan).

This heat lightning phenomenon supports the method of judging how far a thunderstorm is from you. Count the seconds between when you first see the lighting and when you hear the thunder and then divide that number by 5 which will tell you how many miles away the storm is from your location. Remember that thunder and lightning occur at the same instant for the thunder is created by the lightning cutting through the air. So if the storm is right above you the thunder and lighting will happen at the same moment (NWS).