§   Cloud base at 6000 m or higher

§   A very thin layer of cloud composed of small ice crystals

§   Usually light white in colour and translucent to sunlight

§   Looks as if the sky is wearing a semitransparent veil

§   The outline of the sun and moon can be clearly seen through it

§   Can cause white or coloured rings around the sun or moon (a phenomenon called halo)