Supralateral arc

Complex halo display. Top to bottom: Supralateral arc, Parry arc, Upper tangent arc, 22° halo. Sun dog to the right of the Sun.
Circumzenithal arc, Supralateral arc, Parry arc, and Upper tangent arc, in Salem, Massachusetts, Oct 27, 2012.

A supralateral arc is a comparatively rare member of the halo family which in its complete form appears as a large, faintly rainbow-colored band in a wide arc above the sun and appearing to encircle it, at about twice the distance as the familiar 22° halo. In reality, however, the supralateral arc does not form a circle and never reaches below the sun. When present, the supralateral arc touches the (much more common) circumzenithal arc from below. As in all colored halos, the arc has its red side directed towards the sun, its blue part away from it.