A personal visit at least daily to the high-risk person is necessary to evaluate their health and their ability to cope with the temperatures. It has long been known that it is hotter in the city than in rural areas. On an average day, the typical American city will be three to five degrees warmer than nearby rural areas. Cities are generally constructed of materials such as concrete and asphalt which absorbs heat during the day and releases heat at night. Cities have more heat generators such as automobiles, commercial and domestic air conditioners and industrial heat sources.
Cities also have less heat reducing vegetation than rural areas.
In cities, buildings are frequently close together which reduces the free movement of air. Close buildings also reflect heat and light onto other structures. Residential cooling can be greatly facilitated through the appropriate planting of heat reducing trees and shrubs around the house. Shade trees on the south and southwest side of the home will reduce the direct sunlight onto the roof of the house in the afternoon. Shrubs planted around windows have a cooling effect on the air entering the home through the windows.