Extreme hot weather causes deaths that are largely preventable. Urban Cool Islands (UCIs) offer a landscape architecture solution that can help mitigate mortality brought on by heat waves. UCIs are designated city shelters that provide people, especially at-risk population groups, protection from extreme heat events. The paper illustrates a methodology to identify Urban Cool Island locations for further development. This design-oriented methodology defines key UCI elements of public accessibility, good air circulation, shade and water availability and treats them as flexible values, instead of fixed, pre-existing features in scientific methodologies. This methodology uses free and open-source software and is easily adaptable to mobile phone alert applications. The German city of Leipzig was used to illustrate the application of this framework.