An explanation for the multiple rainbows
"The multiple arcs are called supernumerary rainbows. They were so named because early natural philosophers could not explain them and considered that they should not be there. They are a diffraction pattern produced when rays passing through small raindrops overlap and interfere. If we are lucky we see one or two, these widely spaced multiple ones are exceptional and tell us that the raindrops were very small and, more unusually, all of the same size."