A term given to urban areas because they are usually warmer than surrounding rural areas. An example of a heat island is Atlanta which is often dubbed 'hot'lanta'.

Causes of increased temperatures in cities are naturally due to human activities. Man-made materials such as concrete and metal have a low albedo, holding heat in much longer time period than natural landscapes. In the evening, after the sun has set, these man-made materials release heat, and thus warm the air. Heat is also generated by moving objects such as cars and trains. The removal of natural vegetation can also increase temperatures since it provides shade. Vegetated areas also create a barrier preventing solar radiation from heating the ground quickly and cools the air through the process of evapotranspiration.