08/08/2026
Ever seen a cloud with a rainbow edge? ☁️🌈
It's called cloud iridescence.
It happens when sunlight shines through a very thin cloud made of tiny water droplets that are all almost exactly the same size. The light bends around the droplets and spreads out into colours. That's called diffraction.
It's different from a normal rainbow. A rainbow is light reflecting inside raindrops. This is light bending around cloud droplets at the edge of the cloud, which is why you see the colours right on the cloud itself.
You see it best when a fresh, thin cloud passes near the sun. Best not to look straight at the sun to find it. Use your hand or a building to block the sun and look just to the side.
Caught this one over Mancheser this morning.
