Swackett Fun Fact: The halo around the sun or moon is a layer of cirrus clouds made of ice crystals. These ice crystals act as tiny prisms,forming a white or sometime colorful halo around the sun or moon. This cirri-stratus cloud often indicates an approaching warm front and an associated area of low pressure. Rain or snow will not always follow, but there is a higher probability of it after a halo is seen, and the brighter the circle, the greater the probability.