Beautiful double rainbow seen over Philadelphia and the Delaware Valley

PHILADELPHIA (CBS) -- After a cloudy and at-times gloomy Saturday, parts of the Delaware Valley were treated to a spectacular sunset and double rainbow at the end of the day.

Lots of photos and videos of the bright rainbow and orange and pink skies seen across the region were shared on social media, from Philadelphia to South Jersey and Delaware.

But just how rare is a double rainbow?

A full arc double rainbow is somewhat rare and typically occurs early in the morning or late in the day when the sun is at a lower point in the sky and there are light rain showers in the area.

Normal rainbows are created when sunlight is refracted off a raindrop, separating the various colors from the wavelengths of light into a band of red, orange, yellow, green, blue, indigo and violet, or what we commonly refer to as ROYGBIV. Red is the top color in the band and violet is at the bottom.

A double rainbow is also light refracted off raindrops. It will be near but above the main rainbow but not as bright or colorful. The color bands will be reversed, with violet at the top position in the band and red at the bottom, or VIBGYOR.

Folklore says seeing a double rainbow can be good luck and means several things, including a transformation or a bridge between physical and spiritual worlds, or confirmation you're on the right path in life.

And what about a triple rainbow? They have been seen before, but those are extremely rare.