Sunlit fell and rainbow colours

I was driving to Troutbeck nr Penrith this morning and saw these rainbow colours on the fells. I had a couple of minutes to spare so pulled over with the camera. There was a mixture of light rain and sunshine which created the rainbow colours. I'm sure there's a name for it but I have no idea what it is.

Considering the weather started off quite rough this mornig it got smoother and smoother as the day went on and I actually managed to get some gardening done :)