(CNN)Rare pink rainbows were spotted Monday evening in the south and west of England.
Rainbows are, as you may remember from grade school, a spectrum of light created by refraction and reflection. They appear in the sky after rain and are rare enough that people pause when they see them.
But pink rainbows? Those are even more rare -- as evidenced by the chatter these are causing on social media.
Pink rainbows typically appear at sunrise and sunset, due to the position of the sun in the sky.
Sunlight is forced to travel through a thicker portion of the atmosphere during these times of the day, CNN senior meteorologist Brandon Miller and CNN's Nash Rhodes explained. This only allows the longer red wavelengths from the rainbow's color spectrum to be refracted.
This phenomenon also was on display in London back in 2017, when wildfires originating in Portugal and Spain turned London's sky red, the pair said. The reddish and pink hue can be amplified when the air is filled with dust or smoke.
Some on Twitter interpreted the illusion -- spotted in Dorset, Somerset and Gloucestershire -- as a positive sign.