COLUMBIA, S.C. — The absence of audible thunder on hot summer nights can create the impression that heat lightning is somehow different or unique, but technically, heat lightning is not a specific type of lightning or even a scientific term.
In fact, what we are actually witnessing is distant lightning from thunderstorms that are too far away for the thunder to be heard.
On clear nights, lightning can travel a considerable distance from storms miles away. While a lightning strike does generate thunder, its audible reach is limited to those in close proximity.
Unlike light, which can travel great distances, sound typically cannot be heard beyond about 10 miles from its source.
Heat lightning, or rather, distant lightning, is much less dangerous than normal lightning because of the distance.