Abstract: The Modular Head Covering System includes a temperature regulation module, an insect-excluding module and a rain cover module. The temperature regulation module can include the following components: a head-encircling member such as a headband, to which a visor, a scarf-like headcover, and a pair of side flaps can be detachably attached in varying combinations for shade, regulation of body heat, and insulation. The headcover attaches within a pocket built into the section of the head-encircling member that crosses the forehead of the wearer. Two notches are cut into the headcover, one on each side, where the pocket ends at approximately the temples of the wearer. Notches allow the attaching edge of the headcover to be fastened within the pocket, and the rest of the headcover to be positioned either over (on the outside of) the head-encircling member or under (on the inside of) the head-encircling member. Thus, these two components function independently of one another across the back of the wearer's head.