The strength of the solar radiation varies with the solar angle [link] which in turn depends on the time of year and time of day. In addition, it is strongly influenced by the cloudiness, which controls the proportion of direct and diffuse solar radiation [link to Urban microclimate]. However, the average solar radiation does not differ significantly between locations in the same geographical region.

Of course, solar radiation is also affected by buildings, vegetation and other objects that provide shade.

• Solar radiation on horizontal surface
• Solar radiation on a tilted plane (sloping terrain)