Friction surfacing (FS), a solid-state joining process, is a coating technology for metallic materials. Friction and plastic deformation enable the deposition of a consumable material on a substrate below the melting temperature. Process temperatures are an important factor determining the quality and geometry of the deposit. A detailed experimental study of the process temperatures during FS of dissimilar aluminum alloys is performed. The process temperature profiles for varied process parameters, i.e. axial force, rotational speed and travel speed as well as process environment, are investigated. The results show that axial process force and rotational speed are the dominant process parameters affecting the temperatures during the FS process. Additionally, backing material and substrate thickness have significant impact on the process temperatures. The correlation of deposit geometry with process temperature shows thinner and slightly wider deposits for increasing process temperatures. This finding pronounces the importance of the temperature for the friction surfacing process with regard to geometry of the resulting deposit.