## 6 Conclusions  
A new GIS-based framework designed to detect UHIs and identify the most critical urban areas during heatwave events is proposed. This approach applies the FCM algorithm with remotely sensed LST and NDVI data to detect and assess the spatial distribution of UHIs, where the optimal number of clusters is determined using well-known validity indices. To assess the reliability of a potential urban hotspot and confirm its identification as a UHI, a reliability index is computed.  
The study was carried out within the urban framework of Naples, Italy, chosen for its notable attributes of elevated population density and significant urban development.  
The application of the FCM algorithm, known for its computational efficiency, enables the proposed methodology to be effectively applied to remotely sensed imagery. Furthermore, the use of various validity indices allows for the determination of the optimal number of clusters, even in the presence of noise in the data. An additional advantage of the proposed UHI detection method is the assessment of the reliability of UHIs, which represents a quantitative measure of the accuracy of the results and provides, in contrast to other UHI detection approaches, a decision support tool for assessing the accuracy of UHIs.  
A primary limitation of the proposed method lies in the relatively low resolution of the LST raster derived from satellite-based thermal imagery. To potentially enhance the spatial resolution of the LST dataset, the use of thermal cameras mounted on drones could be considered. However, this would necessitate the deployment of specialized equipment and costly data collection campaigns to comprehensively cover the entire urban area, with the added challenge of the duration of such efforts potentially exceeding that of the heatwave event itself.  
Future research will focus on further improving the precision of this detection method and conducting additional experiments across different urban environments and heatwave scenarios. In particular, the framework will be integrated with heatwave vulnerability and impact/risk models to provide decision makers with a comprehensive tool to support the assessment of adaptation strategies in UHIs with high risks/impacts for residents' health. Finally, this work can be addressed in future multidisciplinary research in which the results will be further explored at a detailed scale with on-the-ground measurements, and the contribution of urban analysis and planning specialists will be necessary to assess optimal mitigation strategies and to evaluate the costs of the planned actions.  
**Author Contributions:** Conceptualization, R.C., B.C., V.D., F.D.M. and V.M.; methodology, R.C., B.C., V.D., F.D.M. and V.M.; software, R.C., B.C., V.D., F.D.M. and V.M.; validation, R.C., B.C., V.D., F.D.M. and V.M.; formal analysis, R.C., B.C., V.D., F.D.M. and V.M.; investigation, R.C., B.C., V.D., F.D.M. and V.M.; resources, R.C., B.C., V.D., F.D.M. and V.M.; data curation, R.C., B.C., V.D., F.D.M. and V.M.; writing--original draft preparation, R.C., B.C., V.D., F.D.M. and V.M.; writing--review and editing, R.C., B.C., V.D., F.D.M. and V.M.; visualization, R.C., B.C., V.D., F.D.M. and V.M.; supervision, R.C., B.C., V.D., F.D.M. and V.M. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This study was carried out within the RETURN Extended Partnership and received funding from the European Union Next-GenerationEU (National Recovery and Resilience Plan--NRRP, Mission 4, Component 2, Investment 1.3--D.D. 1243 2/8/2022, PE0000005.  
**Data Availability Statement:** The data presented in this study are available on request from the corresponding author.  
**Conflicts of Interest:** The authors declare no conflicts of interest.