Heat islands are urban areas that can have higher temperatures than surrounding rural areas with more greenery.
Heat islands are caused by a number of factors including:
More natural, often rural areas with greenery may reflect more light, release moisture and provide shade.
There are ways to help reduce the effect of heat islands such as planting more urban trees, or using green roofs.
Deciduous trees have the handy feature of providing shade for a house in the summer while letting light through in the winter when the leaves fall.
Learn more about the heat island effect