Using Google Street View photographs to assess outdoor thermal discomfort and heat perception due to heatwaves in the urban environment

The outdoor heat comfort of city dwellers is negatively affected by heatwaves that are becoming more frequent and severe with the ongoing climate crisis. As such, assessment of outdoor heat comfort has become an important ingredient of successful urban adaptation strategies. However, systematic assessment of long-term heat perception across spatial points is challenging. We present the results of three studies in which we demonstrate how heat-comfort expectations can be assessed with respect to sampled spatial points using Google Street View photographs of sampled locations. Using highly variable samples of residents from two Czech cities (total N = 1,877), we demonstrate that long-term outdoor thermal perceptions associated with specific spatial points in cities and elicited through an online survey can be expectedly traced back to average surface temperatures observed at those points and to properties of those places (e.g., presence of green and blue infrastructure and shading). Moreover, we also demonstrate that such outdoor thermal perceptions predict everyday outdoor activities of people (e.g., preference for walking route and preference for a waiting place) as well as general place preference. We conclude that long-term heat perception elicited through an online survey complemented with visual representations of respective spatial points provides important input for urban planners. Thanks to its scalability and coverage of systematically sampled spatial points, this method represents an important addition to existing approaches based on in situ surveys and mental maps.