 Sunlight reflected off walls and the ground also contributes to daylight.Each climate has different composition of these daylights and different cloud coverage, so daylighting strategies vary with site locations and climates.There is no direct sunlight on the polar-side wall (north-facing wall in the Northern Hemisphere and south-facing wall in the Southern Hemisphere) of a building from the autumnal equinox to the vernal equinox at latitudes north of the Tropic of Cancer and south of the Tropic of Capricorn.