In densely built-up cities, urban green spaces such as gardens, parks, forests, and green roofs provide an important contribution to maintaining urban quality of life and human health. Phenomena such as heat stress and the heat island effect can thus be reduced as a result of local climatic balancing. To make the according ecosystem service climate regulation of urban green infrastructure measurable, and thus specifically controllable, a country-wide applicable indicator has been developed. For the ecosystem service indicator “urban climate regulation”, both the supply of climate-regulating services by urban green spaces and the demand for them by the residential population are recorded. Based on regularly available nationwide geodata, a specific cooling capacity value is determined for the most important urban surface types, using tree canopy and ground cover, also taking into account area sizes and location characteristics. This cooling capacity value is related to the affected residential population in the neighbourhood. Overall, 76 % of the population in the 165 German cities studied can benefit from high or very high cooling capacities in their close living environment. In 37 cities, over 85 % are provided with good or very good cooling capacity by green infrastructure. The proposed indicator enables a comparison between the cooling capacity of individual land types, city districts, as well as entire urban areas and can consequently be a professional planning and decision-making basis for resilient urban development. The planning of nature-based solutions is favoured because win-win situations can be identified as well as efficient measures in terms of the number of people affected.