heat lightning

American  

noun

1. lightning too distant for thunder to be heard, observed as diffuse flashes near the horizon on summer evenings.

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heat lightning British  

noun

1. flashes of light seen near the horizon, esp on hot evenings: reflections of more distant lightning

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heat lightning Scientific  

1. Intermittent flashes of reddish or orange light near the horizon, usually seen on a hot summer evening and unaccompanied by thunder. Heat lightning is thought to be the reflection of distant lightning on clouds. Its color is believed to be due to the refraction of light in the atmosphere.

2. See also sheet lightning See more at lightning

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Etymology

Origin of heat lightning

An Americanism dating back to 1825–35

Example Sentences

A flash of heat lightning lit up the sky over the mountains and there was a low rumble of thunder.

From Literature

She recalled certain images: heat lightning traveling from cloud to cloud, tall grasses, gas flares on the horizon, droves of red-winged blackbirds.

From New York Times

Extremely dry ground and hotter than average temperatures, combined with heat lightning and strong winds, have caused the fires to spread aggressively.

From BBC

When word got out about Mr. Sloan, excitement would spread like heat lightning across the islands.

From Literature

The afternoon clouds look like mountain ranges, enhancing the lush Irish topography, and later there is heat lightning in the distance, which lights up the horizon like an old projector.

From Los Angeles Times