A Sunset Rainbow

We were driving south in pelting rain and as the setting sun- a fuzzy orange ball- slipped into the space between the overcast and the horizon a rainbow duly appeared in the dimness over to the east. It was a fairly drab rainbow- because there wasn't much light to power it- but it stuck around and must have been visible, coming and going, for about a quarter of an hour.

A sunset rainbow is something I can't think I've ever seen before.