"All you have to do is to touch your eyes with the magic wand called: I have to know where I have to heed to”
(Marcel Minnaert)
Halos are arcs and spots of light in the sky caused by refraction and reflection of light from ice crystals. Ice crystals generating halos mainly exist in high clouds (cirrus and cirrostratus). But halos can also be observed in falling snow crystals, freezing fog, on snow covers and on surfaces covered with hoar-frost.

Contrary to rainbows, these atmospheric phenomena are hardly common to anyone. But there are some types of halos which can be as colourful and bright as a rainbow. And halos are not very rare. In average it is possible to observe halos on 6 to 7 days a month. The following pages are designed to get you in touch with the variability of the different types of halos and to encourage you to observe these fascinating sights in the sky yourself.

Kinds of halos
How to observe halos
Statistics and essays