When observed, a circumscribed halo is normally oval in shape and tangential to the 22° halo directly under and above the sun. It form when sun rises and the upper tangent and lower tangent arcs extends into each other and closes in on the 22° halo. As the sun rises above 70° it basically covers the 22° halo.
A circumscribed halo is generally weaker than but more intensive in colour than the 22° halo. Like many other halos, it is reddish on the inner edge facing the sun while bluish on the outer edge.