Building surfaces receive varying amounts of solar radiation depending on the climate and latitude of the site and the orientation and tilt of the surface. Solar radiation entering through windows can contribute a significant amount of heat into the building, which can be beneficial when heating is required but can also be a liability when cooling is needed. The under-heated period during which the windows must be protected from solar radiation is also indicated by the shaded area in a horizontal sun path diagram as determined by the analysis of climate data and solar geometry. Sun path diagrams can be used to determine solar potential of a location, especially to determine comfort, the placement of photovoltaic systems, or passive gains in a solar building. Buildings that are away from the equator receive more solar radiation in equatorial-facing facades as the building is located farther away from the equator.