Thermal comfort in urban areas on hot summer days and its improvement through participatory mapping: A case study of two Central European cities

•Mental component of thermal comfort can be studied using participative mapping.•Street trees and city parks perceived as the best for heat mitigation in urban design.•Water elements are less frequently suggested in heat stress mitigation.•Uneven spatial distribution of coolspots should be addressed in urban planning. With increasing urbanisation and climate change, citizens are more frequently exposed to heat stress. In the current pragmatists’ discourse, efforts to adapt cities to deteriorating climate conditions should reflect not only the objective (physical) effects of the proposed measures, but also citizens’ preferences, which influence the perception schemata and mental image of a place. This study employs the innovative approach of mental mapping, using an online survey to identify mental hotspots and coolspots in two Central European cities of Plzeň and Olomouc (Czechia). Map points and polygons, indicating locations thermally (un)comfortable to individual respondents, are combined into aggregate mental maps. Personal behavioural adaptation measures and citizens’ preferences for measures ameliorating thermal discomfort in thermally uncomfortable areas are analysed. The results show that the most preferred measures for improving thermal comfort are trees and parks, and a combination of greenery with blue elements. Other measures, such as temporary greenery, green roofs and facades, exterior shading elements, water spraying and misting, and street sprinkling, are substantially less frequently proposed. However, there are spatial differences between the preferred measures. The character of mental coolspots confirms citizens’ preferences for trees and parks and its synergy with blue elements and provides inspiration for positive change in (mental) hotspots. Moreover, the uneven spatial distribution of mental coolspots in the studied cities revealed neighbourhoods with few or no cooling opportunities in public areas.