(WHTM) — Picture this: You’re on your balcony or patio when the sun is going down. The temperature is in the 90s and the humidity is around 80%. You look in the distance and see a large cloud. You can see many flashes coming from the cloud, but you can’t hear any thunder. You may think you are seeing something called heat lightning.
But, does heat lightning actually exist?
The short answer: No. But, don’t stop reading! We can explain.
“Heat lightning is simply lightning that you see from a long-distance away. Since the speed of light is faster than the speed of sound, you can see lightning strikes from a farther distance than you can hear them. There is thunder out there, too, but you, the observer, are too far away to hear it. The heat from the lightning bolt causes a disruption of the air molecules around the strike itself, and that leads to the sound of thunder,” abc27 meteorologist Dan Tomaso said.
The sound of thunder can only be heard for about 10 miles from a flash, according to the National Weather Service (NWS). So if you are over 10 miles away, all you are observing is lightning.
The NWS explains that mountains, hills, trees, or just the curvature of the Earth can prevent the observer from seeing the actual lightning flash, leading people to believe they are seeing heat lightning when only a faint flash can be seen. That flash is the light being reflected off higher-level clouds.
The Farmer’s Almanac website believes that the term “heat lightning” comes from the fact the effect comes from warm, humid nights, typically found during the months of July and August. A hazier sky means that light has more surface to bounce off, hence seeing a faint flash.
Tomaso thinks word of mouth may also be a reason people think heat lighting exists.
“I think that people have mostly heard what heat lightning is throughout the years from older relatives or word of mouth. Lightning is essentially a heat or energy release in the atmosphere. It can be thousands of degrees hot! But heat does not generate lightning,” Tomaso said.
Anytime you see lightning and hear thunder, you may be close enough to be struck, so when thunder roars, go indoors.