Rainbows and droplet size

There was a fabulous rainbow this morning. You could see the supernumerary bow underneath it. This is produced by interference whereas the main rainbow is by refraction. Turns out it was explained by Thomas Young by noting that a single reflection in a droplet could produce different path lengths and thus interference effects. See here. I also found this which says that strong red at the top of the rainbow means heavy rain but that a supernumerary bow means small droplets. This site shows how droplet size affects what you see. Looks like the droplets might have been 800 microns today.