During or near a full moon on clear nights, a lunar rainbow or moonbow is sometimes formed by the water of the falls.
The formation of a moonbow at Cumberland Falls is aided by a combination of steep gorge walls, which reduce dissipation of the waterfall's mist by wind, and a wide gorge which allows increased levels of moonlight.

It is the only location in the Western Hemisphere where moonbows are known to appear with regularity, and the Kentucky Department of Parks publishes schedules for visitors.

The ability of visitors to see a moonbow may vary with water level.
At low levels, the falls may not produce sufficient mist for the phenomenon.
Conversely, if conditions include substantial downstream wind, this may increase the level of mist and make a moonbow more likely to be visible.
During or near a full moon on clear nights, a lunar rainbow or moonbow is sometimes formed by the water of the falls. The formation of a moonbow at Cumberland Falls is aided by a combination of steep gorge walls, which reduce dissipation of the waterfall's mist by wind, and a wide gorge which allows increased levels of moonlight.
It is the only location in the Western Hemisphere where moonbows are known to appear with regularity, and the Kentucky Department of Parks publishes schedules for visitors.
The ability of visitors to see a moonbow may vary with water level. At low levels, the falls may not produce sufficient mist for the phenomenon. Conversely, if conditions include substantial downstream wind, this may increase the level of mist and make a moonbow more likely to be visible.
Cumberland Falls