Abstract With the European continent heating up faster than ever, cities are facing major challenges protecting their population from the effects of climate change. Heat can have devastating effects on people’s physical and mental health with particular significance for the known vulnerable groups - the elderly and young children, people with pre-existing conditions, those who are pregnant and those who cannot protect themselves sufficiently for various reasons plus of course people working outdoors. Following the 2003 heat wave, the city of Frankfurt/Main registered a significant rise in mortality and morbidity, leading the Health Protection Authority to be increasingly concerned with heat-related health problems in the Frankfurt metropolitan area. The city has since developed various systems to protect the population from extreme heat and developed an all-encompassing climate change action plan (CCAP). Part of the CCAP is the provision of cool spaces to provide refuge from the heat for the public and implementation of this project started in the summer of 2022. However, with no legislative basis on which to build such a platform, some creative measures were required to ensure its success. Here, we will not only present the challenges we faced but the solutions we found - and the results of our currently ongoing evaluation of the actual use of our cool spaces to help other cities make their journey to similar measures easier. Starting with a brief overview of the CCAP, we will show the cool spaces’ place within the strategy, followed by our original plan of action and what happened when this plan came into contact with the reality of life in a large and diverse city. We will touch on climate injustice and the difficulties in reaching those parts of the population who actually need protection the most. Finally, we present our evaluation strategy and results together with the adjustments we are considering in moving forward with this climate change protection measure. Key messages • (Establishment of) climate change adaptation measures should urgently be enshrined in law. • Health inequality corresponds to climate inequality and continiously challenges adaptation measures.