Sun Dog - During and After

"The halos (or, sometimes known as "sundogs" around the sun) are usually seen when there are high clouds overhead. Those clouds are made of tiny ice crystals, which will refract the sunlight much like a prism will. And voila! You have a rainbow halo around the sun. It works the same way with moonlight. It's usually a sign that rain is on the way, as high clouds usually precede a storm front." - [link]