Two of the fields that have emerged in the science of cities are urban climatology, historically focused on local to metropolitan-scale meteorological processes, and urban complexity science, focusing on population growth and emergent scaling behaviours across multiple cities. In this chapter, obstacles and opportunities for effectively integrating these two research tracks are discussed. Specifically, it is shown that the integration of fine and coarse-grained approaches from meteorology, hydrology, and statistical physics offers an effective theoretical ground to describe complex cities-biosphere interactions and disentangle the factors leading to the emergence of distinctive urban climates. Such a convergence of disciplines is key to address the complexity of cities and the challenges posed by global urbanization.