The Report, led by POLITO and co-led by SDU, presents the Preliminary MAINCODE Methodology. It represents a key milestone within MAINCODE Work Package 1 and aims to provide a solid basis for validating the MAINCODE Methodology, as well as to inform and support the development of the MAINCODE pilot cases. To this end, the Report focuses on the analysis of methodologies adopted for the implementation of climate shelters in school settings across the 22 selected MAINCODE case studies. Finally, the Report provides a methodological framework to guide and support the analysis, development, and implementation of Urban Climate Shelters in schoolyards.