Sunlight in the broad sense is the total spectrum of electromagnetic radiation given off by the Sun. On Earth, solar radiation is obvious as daylight when the Sun is above the horizon. This is usually during the hours known as day. The closer one gets to the poles, however, the more this varies; near the poles in summer, sunlight also occurs during the hours known as night, but not at all in winter at any time. When the direct radiation is not blocked by clouds, it is experienced as sunshine, a combination of bright yellow light and heat. The heat on the body, on objects, and so on, that is directly produced by the radiation should be distinguished from the increase in air temperature.
The World Meteorological Organization defines there to be sunshine when the direct irradiance from the Sun measured on the ground is at least 120 Wm-2.
In cold countries, many people prefer sunny days and often avoid the shade. In hot countries, the converse is true; during the midday hours, many people prefer to stay inside, out of the heat, and, if they do go out, seek out the shade, which is provided by trees, parasols, and so on.
Sunshine into buildings is often blocked by window blinds, awnings, shutters or curtains.
For many people, an additional or even the primary purpose for sunbathing is to darken one's skin color (get a sun tan) as this is considered in some cultures to be beautiful and is associated with outdoor activity, vacations or holidays, and health (all types of skin cancer have been linked to excess sunlight exposure). With nude sunbathing an even sun tan can be obtained.
