A portable shelter comprises a pair of base members pivotally supporting a plurality of support arches spanning therebetween. Each support arch is hinged at an apex thereof to permit folding of the arch support in half for storage. The support arches are coupled to the base members for pivotal movement about respective pivot axes in which ends portions of the support arches are offset both axially and radially relative to the respective pivot axes from the other support arches to permit the support arches to be nested within one another flat against the ground prior to folding to enhance the compactness of the shelter in storage.