The purpose of this paper is to understand the climate of the street and how it can be modified to better meet the needs of the street and the user groups. At the same time the conditions of the street and its surroundings also has to be taken into account. To accomplish this it is necessary to have a broad knowledge of the climate conditions in the city. Therefore an overview of the climate elements and how these are modified in the built-up areas are given. The part of the paper which deals with the city climate has a global approach to be able to give an as complete picture as possible. The main issues in this chapter are the modification of the wind, the heat balance and the water balance that a city generates and an understanding of how these are altered. After shedding some light on the special environment in the city, the next chapter focuses on the street climate and how the conditions in street canyons are affected by different factors such as; street canyon geometry, building composition, orientation and localisation of objects and vegetation in the street canyon. Since the wind is the climate element that is most important to control in the colder regions, which Sweden belongs to, according to several authors there is an emphasis on this element in the chapter. Furthermore there is a need to bring forth this climate element since the center of attention usually lies on the solar access and very often is the wind ignored and seen as an element which can not be modified. The following part of the paper is an attempt to apply the knowledge gained and to give some advice of how one can plan a city, develop and create a street canyon and place objects and vegetation in order to accomplish a better street climate depending on the conditions and use of the street and the needs from the user groups. Finally this thesis is summed up by a reflection over the work and some personal thoughts. In the very end of the paper there is an enclosure which deals with some general climatology.