Blue spaces in cities are often regarded as adaptation measures that effectively reduce urban heat. Therefore, urban professionals like to integrate blue infrastructures in climate resilient designs. However, several studies indicated that the cooling effect of small water bodies is often small or absent. This poster will inform about the actual cooling potential of small blue spaces such as rivers, ponds, canals and fountains. Simulation results from the REALCOOL project will be complemented with measurements and questionnaire surveys from other studies and relevant scientific literature to illustrate the negligible cooling impact of small blue spaces for climate resilient urban design.