This exploratory research paper proposes a participatory citizen science methodology with the use of vehicle-mounted MeteoTracker mini-weather stations for urban heat mapping appropriate for Mediterranean cities. Focused on the Metropolitan Athens area, the research completed 426 routes over two summers, collecting 170,546 valid measurement points. The methodology, involving participant recruitment, route determination, and data collection, successfully captured microclimate variations. The approach contributes to European Union initiatives on high-value dataset collection, enhancing data-driven decision-making for climate adaptation planning. The research underscores the importance of participatory methodologies in addressing inner-city vulnerabilities and inequalities, emphasising the need for localised data for effective urban green planning in the face of climate change.