Climatic conditions in an area can be affected by the landscape, relief and activities taking place (both human and natural). Climate can alter over time and space.
Within a climatic region, the climate may vary from place to place, eg the top of a hill, the sunny side of a hill, the shaded side of a hill and the bottom of a hill. These areas with their small variations are called microclimates.
Physical features such as water areas can have a cooling effect on the land. Trees can shade the land, also making it cooler. Human features such as walls and buildings will shelter against the wind, making it warmer. Buildings which are heated may also give out heat (radiate), which again makes it warmer than the surrounding landscape. Due to human activity, the temperature in an urban microclimate is higher than that of the surrounding areas. Urban areas are said to be urban heat islands as under calm conditions, temperatures are highest in the built-up city centre and decrease towards the suburbs and countryside.