A photovoltaic (“PV”) array includes a plurality of interconnected PV modules. A PV array perimeter assembly may be positioned along the perimeter of the PV array to restrain horizontal movement of the array. For improved wind performance, the PV array perimeter assembly may include curbs that come with pre-attached flexible wind deflectors configured to prevent wind from penetrating underneath the PV array. The flexible wind deflectors may be made of a flexible membrane and may include water drainage holes to allow water to flow out of the PV array. The curbs do not necessarily have to be fixedly attached to a rooftop, and may include ballasts to prevent array movement. Embodiments of the invention may be employed on PV arrays installed on flat rooftops, and are especially advantageous when used on uneven roof surfaces.