To study the influence of climate and weather on the use and perception of urban outdoor spacesThe objective of the research presented in this paper is to describe how climate influences the use and perception of the urban outdoor environment. This has implications for the design of public spaces and the relation between indoor and outdoor spaces. The objective refers to regional and micro climatic differences between places as well as seasonal and weather variations in the same place. It refers to the outdoor climate as a natural element in the outdoor environment in contrast to the controlled indoor climate.Urbanization leads to increased indoor staying and increased energy-consuming air-conditioning: Urban people spend more and more time indoors, not only in their private homes and work-places but also in public indoor spaces. Many formerly outdoor public functions, from all kinds of markets to sport arenas, are being built in and climatically and otherwise controlled. Air-conditioning these huge volumes is energy-consuming, and thus contributing to global warming. In a cold climate indoor spaces support social activity but discourage outdoor activity. Many people, however, believe that it is healthy to be outdoors, probably more so in a cold climate, where more effort is required to adjust the activity to the outdoor conditions. The outdoor environment then provides the climate and space for physically active activities. Moreover psychological research points at the restoring effects of “nature” and outdoor activities. Simultaneous climate measurements, observations and interviews in urban public spaces in two cities; the results presented are based on field studies of climate and behaviour in outdoor and indoor spaces in two Swedish cities with different climate, Göteborg situated at the 58th and Luleå at the 64th Northern latitudes. The outdoor climate has been measured, human activities have been observed and people being in the spaces have been interviewed about their perception of the weather, the place, their reason for being there, etc. These field studies cover four hours around midday during some twenty days throughout the year in each of the two cities. In addition habits and attitudes related to climate and outdoor staying have been investigated through mailed questionnaires to people working or living near the study areas. Urban people demand comfort and contact with the natural elements: Big differences were found in the use of the different spaces and also differences between the spaces according to their function, which could to a large extent be explained by the weather. The use of the spaces and the perception of climate and weather, however, were also related to the season and the local climate. The results give further arguments for taking the local climate conditions into account in urban design. They show that urban people demand comfort and contact with the natural elements. Tilläg: In urban planning it is becoming more and more important to declare how different design alternatives impact on the environment and the effect this might have on people’s health and well-being. New types of buildings are introduced. New urban life styles spread regardless of climate. People go outside to sense the outdoor weather, and they demand comfort. It is therefore important to have methods and criteria to assess the microclimate with respect to how the urban spaces are perceived and used. Planning mistakes are often difficult to make up for afterwards and possibilities to create sheltered spaces should be exploited, i.e. to spot the warm spaces for the increasing number of outdoor cafés.